The reply from warpus in post #2 sums up the obvious things for me as well. I suspect eating meat, or at least meat of the sort many of us eat today (intensively factory-farmed) will seem quaint. Perhaps it will all be lab-grown some day; perhaps you might have pasture-raised or wild-caught meat only a few times a year on major holidays.
A little harder to predict is what the views on sexuality will be in 50 years. I'm skeptical of how being trans is increasingly promoted as a good thing, and in some cases glamorized, without much mention of the negative side effects, including the hazards of moving into it too quickly. If you have the money to pay for it, are old enough to really understand the consequences, and are really sure and have been for a long time, go for it. But I worry that it's being over-promoted among the youth of today, and that could have serious consequences for some who jump into it without really knowing what it means long-term. And I'm not interesting in dating someone who has transitioned.
I also think identity politics and the focus on race is currently overstated. To be sure, there are racial issues in society that need to be addressed, and that has become worse over the past 4 years. But I'd rather focus on economic inequality than slavery reparations. Today it seems like the focus is on the opposite, and although I suspect that will change over time, I could be wrong. But IMO, focusing aid by race will only further drive a wedge between society, and would in fact increase racism among the poor of races that did not receive aid (and would, in that event, in fact be discriminated against racially). Focusing aid based on economic status would be a net benefit to races that are on average disadvantaged today, without encouraging a racist backlash by those who are poor and don't receive aid. That alone won't make everything right - there is also opportunity to better enforce anti-discriminatory statutes already on the books, and likely add a few more targeted regulations where warranted - but my potentially old-fashioned-in-the-future view is that identity politics and overtly favoring certain races in economic aid would only make the situation worse, not better.
In less serious matters, my grandkids would almost certainly find my view that the best way to back up your data is on external hard drives, rather than to the cloud, to be outdated. Along similar lines, my lack of an account on popular social networks and my general lack of use of the Internet on my phone also likely would be seem as outdated. But you could make a good case that those habit are already seen as outdated by people 20 years older than I am today, and there's no need to wait for grandkids for that.
