I find the learning curve of the game the most satisfying and fun part of the game. I like gathering knowledge about the game and improving, also teaching new players that enter the game.
It is definitely not boring, but might be repetitive for some people, because you play the same game on the same map every time. But then again, Counter-Strike, also a very big game, doesn't have a lot of new things being introduced in the game, yet people still find it fun to play.