things generally haven't been great since the industrial revolution, but the big thing is that nowadays we're just soaked in stress at all times with little reprieve.
Used to be in the past that things were generally chill except for big stressful events that happened every now and then, but nowadays things are constantly loud, we constantly have to hurry to do stuff, we constantly have to worry about affording basic things and knowing that we'll probably never own a home, etc etc etc.

We're also in the middle of a loneliness epidemic, it's basically standard at this point to have few friends and not hanging out with people anywhere near enough. Add these things together and you get people being miserable.