If someone from the 1950s suddenly appeared today, what would be the most difficult thing to explain

That you might get pulled over and arrested driving home from a night at at bar.

When I was 18 in 1957 I can’t recall ever knowing a girl who had a car licence. This was in the UK, things may have been different in the US.
People from the 50’s would be surprised by the lenient sentences handed out to murderers. Here in Australia it’s common for murderers to be out of prison in 3 or 4 years. I remember a guy got 28 months actual prison time for stabbing to death a taxi driver because he “hated Chinese”.

True, but the early Pill frequently had dreadful side effects (in part because the dose turned out to be orders of magnitude higher than what was necessary), kidney transplants were really only feasible between identical twins, and open-heart surgery was in its infancy, mostly performed on children and younger adults with birth defects, and certainly not done almost routinely on senior citizens.

Rock Hudson too.

My mother had a friend who died about 10 years ago who lived with her “best friend” for more than 50 years, and in the 1970s, they bought a house together when they found out it was possible for single unrelated adults to do that. Hello, they were a lesbian couple.

And he wasn’t born until 1961, in Hawaii, which was not a state yet in the 1950s.

I have a PBS program about “Laugh-In” on my TiVo from the late 1960s, and they have excerpts from programs about 20 years in the future. Two of the clips include a reference to “President Ronald Reagan” and “The Berlin Wall has been torn down…” Both lead to lots of laughter.

ETA: How about a black First Lady who’s also a graduate of Harvard Law School?

What about our money - how the role of cash has dramatically decreased and that most of your money is never “actual money” at any point (I get paid by an automatic direct deposit and then I go online and direct some of that electronic money to my credit card company, where it pays for stuff I bought with a credit card.) I have less than a dollar in my wallet and almost never have cash with me at all. I don’t have any kind of bank book or anything (although surely an intelligent person would grasp that I do, it’s just on a website now.) But I don’t have to worry about when the bank closes or when Western Union closes, etc.

ETA - I’m only 34 and I well remember that when we went on family trips when I was a kid, Mom would go to the bank and take some cash out. Because we’d need it.

You might have a hard time explaining to them that they can’t just light up a cigarette anywhere they want.

If you must, here’s an electronic cigarette.

I am pretty confident that people from 1950 could easily get their head around many of our medical advances. They had seen so many amazing things in their own lives. Among other things, X-rays were barely half a century old.

Allow me to ramble on with one example of amazing medicine, from before 1950…

People in the 1950s remembered a time when a bacterial infection was a much more dangerous thing, even a simple cut could lead to death. Even the President’s son wasn’t safe.
Less than a decade after Coolidge’s son’s death, Bayer released the first commercially available antibacterial, Prontosil.
In 1936, Prontosil was used to save another President’s son’s life, that of FDR Junior.

About the same time, the Pasteur Institute figured that the magic of Prontosil wasn’t in the fancy dye portion of the molecule, but in the common sulfanilamide molecule, generated as a metabolite in the body. This meant any Tom, Dick, or Harry could create the unpatentable sulfa drugs, and they did.

This must have been an amazing era for medicine, with the first true hint that bacterial infections could be targeted by a simple organic compound that could be manufactured.
Penicillin had been discovered earlier, but it was more difficult to produce, so sulfa was the first great antibiotic. And just like atomic energy, antibiotics were not well understood and were misused. Sulfa was pretty much burned out by the end of WWII, with massive Army testing and other things causing resistant bacterial strains to appear.

I would be remiss if I didn’t mention Elixir Sulfanilamide. In 1937, the tragic results of using a poisonous industrial solvent in a cocktail of sulfa brought about sweeping changes, giving birth to the FDA and the pharmaceutical industry that we see today. A hundred people died, but their deaths have doubtlessly resulted in far more lives saved.

That episode should be required reading for everyone in the pharmaceutical industry.

I’ll get off my soapbox now.

I was a teenager in the Uk in the 50s. I think that there is some sense in most of the above posts but…

We were well aware of homo’s/queers/poofs and even though they lived outside the law, they generally were tolerated. This was apart from a small minority of bullies who would kick the shit out of them just for being different.

The space race was exciting and I and all my friends were avid readers of SF mags and books, so, yes, in some senses we would be disappointed that cars don’t fly and there isn’t a colony on the moon.I just wonder if we wouldn’t find ourselves a little disappointed at the lack of progress.

I think that the hardest thing to get our heads around would be prices. On the one hand, things like a visit to the pictures which cost me the equivalent of 12½p then, costs £6 or £7 now, and I could get four gallons of petrol for £1; while on the other, a small black and white television cost almost as much as a house, and you had to apply for, and join a waiting list, to get a telephone installed.

I think too that we would be pretty amazed by all the furore about pedophiles. Flashers were pretty run of the mill, and something for girls to giggle about; scout and choirmasters interfering with young boys made a salacious paragraph in the Sunday papers, and the joke where I lived, about the next village (naturally) was that the definition of a virgin was a girl who could run faster than her uncle.

If I went 60 years into the future and discovered that dolphins will be walking on land and running their own seafood restaurants, I would call for a time-out and ask what the freakin’ hell happened. I’d double-check the dial on my time machine to make sure I didn’t stumble into an alternative dimension. That’s how I’m interpreting the OP. Not what’s the most difficult thing to explain, but what’s the most mind-boggling difference between now and the 1950s.

Everyone expects the future to be “The Jetsons”. So I don’t think anyone would be completely blindsighted about all the technological advancements.

What would get people most would be the social changes. I don’t know if anything rises to the level of Dolphin Americans, but I do think 1950s people would do a double-take at the accomplishments of black people and women, and the growing social acceptance of gays.

1000 channels of cable television. Many of them program specific (sports, cooking, cartoons, widgets).

The proliferation and mainstream acceptance of pornography.

Female orgasms

Businesses that don’t exist anymore (i.e. Woolworth).

Profanity on primetime television

Television shows staring rude, disrespectful children, dumb ass fathers, and etereal wives

Lotterys and casinos in every state.

Cost of certain things (candy bars, gasoline, cigarettes)

Smoking bans

I don’t really buy that they would be overwhelmed by our technological advances.

Remember that the biggest causes of death – infectious diseases – had recently been conquered, including that old #1 cause, tuberculosis. So expectations for future medical advances were high. Most people would be surprised that cancer is much more likely to be the cause of death now. (Even though that is because other causes of death have declined.)

People also would be surprised that the cruising speed of the most advanced jetliner coming into production today, the Boeing 787 Dreamliner, is slower than that of the most advanced plane coming into production in the late 1950’s the Boeing 707.

Given the hyping of picture phones as early as the 1939 World’s Fair, Skype wouldn’t amaze, especially when it freezes up.

Would changes in attitudes towards African Americans, gays, and illegitimacy shock? Well, this would all depend on what a person’s views were then.

A big change is that you can’t now tell someone’s social class from their clothing. This, and that almost everyone sometimes dresses like a beatnik, would take some getting used to.

Also hard to get used to, especially if the time traveler was past age 30 or so, might be changes in popular music.

What happenned to Jacquel Brel’s predictions:

So, maybe, they would be a little surprised that magnetic tape has died.

P.S. Also very hard for me to get used to would be today’s Broadway ticket prices!

“1) Hitler; 2) Stalin; 3) Walter O’Malley.”

Well, if you saw this, you might think it came true.

An ordinary cell phone could be described pretty succinctly as a telephone that operates over the radio, which is pretty much what it actually is. If they understand what a computer is, you could describe a smartphone as a telephone operating over the radio that is built-in as a component to a computer. Email as a concept is not that different from telex, and they had that back in WW2. An email-capable device is just a portable telex, in a way.

At least by the 1960’s, you had SF shows that showed people with fancy handheld gizmos that did fancy stuff, so you could phrase it in terms of that. “Remember that <device> on <show>? It’s very similar to that.”

Perhaps they might be able to wrap their heads around the physical internet, but I think that the internet-as-a-repository-of-all-human-knowlege-available-for-instant-recall would blow their minds. The internet is not just a physical communications medium. It is a transformative tool in the way we lead our lives.

Need a recipe for cherry pie?
No, you don’t have to call the Aunt Martha or go to the library. Just click a few keys and thousands of recipes appear before your eyes.

Need directions to get from the stadium to the hotel in San Diego or Philadelphia?
No, you don’t have to go to the AAA office and get a stack of maps. Just click in the addresses and you get a detailed map showing driving, public transit, walking, and biking directions in an instant. You can get this between any two points in the world.

Is your credit card payment due today?
No you don’t have to hurry to the bank before they close. You just type in a few keys in your living room and it’s paid.

Do you have to stuff dollar bills in your computer to pay your bill?
No, just give them a bank account number for any bank located anywhere in the country and the money will instantly move to your credit card company.

You need a new alternator for your 1950 Chevy?
No, you don’t have to search junk yards. Just type in a few keystrokes and the mailman will deliver one right to your door. And he’ll do it the next day for a few dollars more.

You miss the last episode of your favorite TV show?
No, you don’t have to wait for reruns. Just call it up on your computer anytime you like.

Want to speculate about how a 1950s person would react to the modern world?
Type in a few keystrokes and people from around the world will be speculating with you.

Want to see midget lesbians nude wrestling in a pool of Jello?
NAH!!! You’re kidding.

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The SPEED with which we can transmit data would be more mind-boggling than the fact that we can transmit data. You might be able to explain the concept that we can reduce a motion picture to a series of dots and then assign a number to each dot, but transmit that over a phone line fast enough to reassemble into a motion picture playing on someone’s screen on the other side of the earth??? In the 1950s, if you made a long-distance phone call, you had to shout and strain to hear over the noise. but now you can get millions of numbers PER SECOND delivered clean and error-free over a phone line right into your living room. And you have a tiny box sitting right there on your table that can process billions of numbers per second.

I think we all underestimate the impact of the internet and how much we depend on it in our daily lives, even if we personally don’t own a computer. I think comprehending what the internet is used for what require a major paradigm shift for someone from the 1950s.

Special taxes to pay for stadiums so millionaires can play a childs game.

Gun control- the active drive to destroy gun rights by our leaders.
Gun rights- people legally walking around with pistols in their pocket was not a norm in most states in 1950.

R-rated movies

Frankly I don’t think there would be just 1 or 2 things that would be difficult to explain. I think the totality of all the technological and social changes would be be overwhelming for most people from the 50’s.

I’m going with computers/smartphones. And not the wow factor of the technology itself. I think our near-constant use of and apparent dependence on computers and smartphones would be really shocking.

We are welded to our iPhones and we are constantly tapping away at them. If there is an IT problem at work, we can’t even do anything. Even factories and farms are run by computers. We play games on computers. We socialize on computers. We read books on computers. We can’t even wait for an elevator without pulling our little computer out of our pockets and playing a few games of Candy Crush.

Yes, there is some degree of hyperbole in the above, but the time traveler would be bowled over by the reality of how we have integrated computers into so many areas of our everyday lives.

ETA - Alley Dwellers post snuck in while I was writing this. Yeah, what he/she said.

Of course it happened in the 1950s.

It’s worth noting that the pill was approved in 1957–but for menstrual disorders, not contraception. It’s contraceptive qualities were well-known by that point. An awful lot of women suddenly were diagnosed with “menstrual disorders” by understanding doctors. It was approved for contraceptive use in 1960 and it became much more widespread after that.

Point being, the pill was actually in use for contraception by 1957.

I grew up the son of a Brooklyn Dodger fan. I have a problem with your order.

Yeah its pretty hard to get my head around and I lived through it. As a kid TRS 80s were impressive. Now the sum of human knowledge (almost) is on my phone. In my pocket. That trumps everything else.