As others have said: (1) people, (2) people, (3) people.
In my line of work I interact with lots of different people. I have come to find that I like the type of people pinball attracts the most. Pinball people are who I want to be around when I have free time. I love going to shows. I love going to tournaments. I love talking pinball with others.
As for playing, I love playing pinball. I could play every day for a couple hours a day and be happy, but I need someone to play with to have the most fun. I was very lucky in that my wife got super into pinball quick right when we started dating (she had never played a game of pinball before we were dating). PavBall actually was the main driver behind a couple of our machine purchases, which is awesome.
The themes that are coming out with new machines today are awesome. It seems like every six months there is a dream theme of some kind coming out. It's really incredible.
For me also Pinside itself is a big part of my enjoyment of the hobby. I've been a moderator here for a long time now. Y'all of course don't see it but the mod team debates (pinball and non-pinball) topics all the time behind the scenes about basically everything...and it's fun (usually).