Some changes may be surprising because the direction has been opposite to that expected. I remember when I was a kid in the mid 60s (so not quite 1959) writing an essay about life in the year 2000. One thing I wrote was that the speed limit through our village was 200 mph. In fact, the speed limit is now lower than it was then.
A little over a decade ago, the Federal Reserve Bank of Dallas published a fascinating report on the hours of work required to buy many different products, and how that changed over the past century. Unfortunately, I’m not aware of anyone who has updated this report, but you can find the original here (pdf). Highly recommended, even if you do nothing but look at the graphs.
In my original cite, milk was quoted at a dollar a gallon.
In this (PDF) official .gov document milk is listed at 50.6 cents on page 31. That would be about 7.5 cents today.
How do you get 7.5 cents?
If milk cost 2 silver quarters in 1959, that would equate to about $6.00 or $7.00 in todays money/federal reserve notes.
OF course I hope everyone realizes that nobody sold milk by the gallon back then, everyone sold it by the half gallon, quart, pint, half pint… (Who the heck would ever want to buy a whole gallon of milk?)
I get that by running the conversion backwards. Good catch. 
That would be about $6.75 today.
I remember (I was four at the time) that we bought milk in a liter jug (Denmark), a horsedrawn milkwagon came and we went out and got the jug filled at the wagon. Bottles was something people had in towns.
Yes, without a fridge you just bought enough for a day. We had a cellar so the milk was cool but I still remember that I really didn’t like milk in summer. It always tasted a little off. My parents got a fridge in 1962 and it was a revelation to me that I actually liked milk in summer.
The flood of immigrants. There are so many in the Washington DC area now that, except for a couple of wealthy enclaves, the Washington area has no more “white neighborhoods.”
Going back to the bottled water …
As a kid in the early 60s, it seemed that pretty much every retail store and gas station had publicly-available bathrooms and a drinking fountain. And public facilities like libraries, schools, or office buildings all had the same thing. So getting water while out in public was not hard.
So the demand for purchased portable drinkable water was nil in 1959 except for people who worked outdoors away from anywhere. And those folks had been carrying their own water in canteens and later coolers since the 1800s.
In the late 60s with the advent of inflation and massive cost-cutting by everybody, those were one of the things which disappeared. Most small retailers still had a bathroom, they just wouldn’t let patrons use it.
With all the unrest and a large increase in the public perception of random crime, in the name of security (or keeping “dirty hippies” out), office buildings added front desks, guards, and started locking bathrooms, at least those near the lobby.
So the public availability of free drinking water went way down. And the seeds of a market were born.
Finally, the huge rise in sales of soft drinks at convenience stores (another mid-late-60s invention) led to a generation (the folks 40-ish now) who spent most of their youth sucking on something. The urge to carry & slurp is still there, even if they’ve decided that water, or worse, “vitamin water” is better than a 64oz cola.
I keep seeing “congestion” mentioned in these threads. A lot of that, I think, is a misconception.
From 1929 to 1949, very few housing units were built in the United States, thanks to the Depression and World War II material shortages. After WWII, the suburbs didn’t pop up overnight; rather, there was infill in the long-dormant pre-Depression-era subdivisions for about ten years before new subdivisions were platted en masse. Low-density suburbs were a response to cities and housing conditions that were considered extremely overcrowded.
Household sizes were much smaller, as were housing sizes. Today, a typical family of three would live in a 2,500 square foot house. In the late 1940s, it would be a family of six living in a 1,000 square foot house or apartment, often with extended family under the same roof.
Roads were also crowded, and traffic congestion was a major concern of planners of the era. The Interstate Highway system was originally planned to serve intercity and interstate traffic, but was later modified to accommodate intracity commuter traffic, largely in response to extreme traffic congestion. Traffic signals weren’t timed, there were no left turn lights, and lannes on wide roads and highways were often unpainted, making traffic jams even more chaotic than today’s tieups.
Ever see a photo of a 1950s shopping center? The parking lot was always jammed. I remember shipping plazas and malls being much busier back in the 1970s than today; it was rare to find a space within a reasonable walking distance to a store or mall entrance. Store aisles were narower, and there was far less space between shelves, store racks, and so on.
Cite.
That would depend very much on where you were. If the time traveler were a Pittsburgher, he or she might be surprised how much the population here has declined. We had 604,332 people in 1960 and have 334,563 now. I don’t know what traffic, employment, etc, was like here in 1959, but I do know it’s not worse now because of population growth. A Pittsburgher from 1959 would probably be surprised at the lack of pollution here, too.