What I like about the Hattrick community is that there are real people and you don't just compete against the computers. You play against each other, but you can also help each other in the forum and talk about everything.
The game concept I like the most is the Special Events system, which allows multiple tactical options that are almost equal in strength. In general I think the Youth Academy is the best feature in the game as it creates a close connection to your own players.
What I like about Hattrick is that there are not 248 925 784 skills that you have to pay attention to. I like that there are several (but not too many) tactics and that they all have weak points that other strategies can beat. I like that this is a slow game, it fits my private life. And that is probably also why I still find it interesting after almost fifteen years.
I would say the community is the strongest reason I have stayed in Hattrick for so long. The game too of course. After having trained my players and played in the French Division 2 for a while, I started focusing on training international players to help the Moroccan team. Today 80% of the defense of the Atlas Lions was trained by me!
Some of my Hattrick friends I've known for more than a decade now, which is longer than quite a few of my real-world friendships. You build up trusting relationships with them, and meet people you'd normally never meet. That's also what I really enjoy about the federations in Hattrick - some are really places where you can share your personal stories. A federation in Hattrick was one of the first places where I disclosed I was going to become a father!
Why I stick around in Hattrick? I think it is love :) I mean, everything I can do to help Hattrick to stay as immersive as it is, is very important to me. I was a moderator, a translator, an editor - just because I felt that Hattrick, in a very peculiar way, was mine. Now I'm a National Coach because of the same reason. I think Hattrick is my game. I want to play forever and stay here with my friends.