[robhack]

I can definitely imagine that if I had been a farmer in middle-age I could have been happier, because I wouldn't have time to get bored, and I would be doing something useful.

In our modern world however, really useful stuff is done by robots or a tiny part of the population. Thus you have to find meaning on your own and that can be quite difficult.

[davidxc]

In my opinion, there are plenty of useful things to do as a programmer. There are many non-profit organizations doing important work that would love to have a volunteer programmer. You could also teach math or programming to high school kids, etc. Paid programming work can sometimes seem far removed from "useful" work, but I think that's partly because of the complexity of society and all the abstractions that we have built. If you'd like to do something that feels more direct, I would suggest volunteering somewhere. But I do agree with your sentiment that finding meaning on your own can be quite difficult.