You know kind of like how you went to the local drug store to buy cocaine, smoked when you were pregnant, etc.
What cha got?
I’m hesitant to say paper money but… paper money.
Carrying around a phone, instead of having it surgically implanted.
Mailing ordinary paperwork like bills or business info through the postal system.
Stamped mail will be the purview of mass mailings and personal “important” missives from stuck-up people announcing their weddings or kids’ major life events.
Smoking pot discreetly so as not to get caught by the fuzz, man.
Driving ourselves.
Buying small, easy to 3D-print objects.
Buying stuff at physical stores rather than ordering and having them Droned to us…
Smoking
Writing with a pen or pencil on paper
I’d say something similar. The amount of paperwork, documents, and such that corporations require is going to be drastically reduced in favor of digital copies. It’s already starting at my company. We digitally upload everything, but we still have mountains of copies at a physical storage site.
In 50 years, this is going to appear absurdly wasteful.
Oh my god yes, stores! I can’t wait for them all to be demolished and replaced with useful things like empty lots.
Also, associated with stores, physical media for any kind of information. CDs, DVDs, Blurays, tapes, floppies, whatever. They’ll all be quainter than snuffboxes one day.
No offense, but I don’t think most of those things will seem “crazy,” just outdated or obsolete.
No slam on religion, but I think 50 years from now people will think we were nuts for allowing religion to influence government policy making. Hopefully they will also think we were crazy for allowing groups to give large amounts of cash to politicians who create policies that directly affect said groups.
Actually, I think the whole keyboard-mouse interface will be obsolete, perhaps much sooner than fifty years from now. And the idea of turning on lights manually will be obsolete; they’ll be automatic, or perhaps voice-activated. Discrete light bulbs will be obsolete. Either walls and ceiling will be illuminated across the whole surface or the entire table lamp will glow.
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Driving your own car. I mean, a HUMAN at the controls of a VEHICLE? That’s just insanely dangerous!
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Boxing. Brain damage for the gratification of an audience? Might as well be gladiators!
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I think our expectations for protective equipment will become deeply ingrained. For example, riding a bike (which I’m sure will still exist) without some kind of gear, perhaps active safety systems like airbags, will seem like driving a car equipped with a giant spike on the steering wheel.
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Going outside for any length of time without sunscreen.
I hope it’s flossing. Because it takes up way too much time.
The media biggie will be paper books -they won’t just be completely digital, but will have been digital so long that keeping paper books around will seem nuts - wasteful, expensive, slow to acquire. I don’t expect everything to be converted to digital, but 50 years on there won’t be much in print that interests most people. Take everything out of my library over 50 years old and you’d clear the shelves down to 3 or 4 books that aren’t available digitally.
Small kid fifty years hence to grandfather who was born in the 1900s: “Is it true that you didn’t have household robots when you were growing up, Granddad?”
Because based on current research and product development, it seems safe to predict that autonomous robots will be common in the future.
If the Jetsons taught me anything, it is that maid robots and automatic dog walkers will be common by the year 2062, which is less than 50 years from today!
Instant access to weird goat porn and pirated software and media for anyone who knows how to operate the Google front page. The internet is still going through its crazy adolescence, but I think it’ll be forced to grow up before long. And maybe it should.
Followed up with, “Gee Granddad, how did you live to 160?” 
Substitute “born in the twentieth century” for “born in the 1900s”.
Sun tanning.