Gaming. I’m in my 30s and the 30s was the age bracket I’ve heard where few can carry on gaming through, because it has a tendency to die here. I piss away so much time doing other things that gaming just takes a backseat. I’m not even married or have kids.
Maintaining relationships with distant (geographic) friends. Everyone moves around going about their life, you slowly lose contact. Not intentional, “I’ll text later” and so on and next thing you know it’s been months or years.
That’s why old people are on Facebook- so we know who’s who at the weddings and funerals.