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!
I started playing Hattrick in the summer of 2002 when a friend, who I played "Fantasy Wrestling" with online, told me about Hattrick. I made many mistakes in the beginning. At that time there was no such thing as mentors or beginners' guides. So my very first club was bankrupt after only a few weeks. Luckily, I was able to restart with a new club shortly after that and then I did a lot better.
I like that Hattrick is a slow game. Here, I have time to think everything over. I also appreciate that Hattrick gives everybody the chance to be the best because you can't buy in-game advantages.
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.
You need solid dedication, a touch of insanity and a whiff of luck to become successful in Hattrick. Oh, and a feeling for mathematics.
One reason I play Hattrick is because I like the cyclical nature of the game. You start with an idea about what kind of team you want to build, then you train long-term (up to 3 years in real life!). While you build, you can test and try to comprehend the aspect of the match simulation that you want to master. I also like the tactical choices you have to make for each match. But the most important component is the community.