We have basically doubled our life expectancy of our species over the last hundred years and (maybe I shouldn't have smoked before this, but I'm going to try!) are starting to really get a good idea of the problems we haven't dealt with ever in human history. Pollution, Pesticides, Farm land abuse, desertification, on and on.
The millennials are the first (here in America) that haven't been sucking water out of lead pipes all their lives. They are really becoming impressive with their productivity, and all the jokes about how un-manly they all are seem to have helped them not be as molest-y which gives women that might not have entered the workplace in the first half of the last century opportunities to advance our economy.
I am pretty excited for our future, with techniques like cover crops and no-till farming, less driving around as people are able to work from home more, everything is becoming efficient enough that we should be more than able to take care of all our vulnerable citizens sooner rather than later. And since they have a much better understanding of communicating online they should be able to find good information to combat the trolling from affecting their understanding of reality (unlike a lot of our older population that didn't grow up with a computer in their pocket).