Why do you love this game?

I've played in about 20 sessions of Call Of Cthulhu now. While I enjoy spending time with my friends, I just don't get what's "fun" about the game.

Rather than just bash the game because I don't like it and list what I think are it's shortcomings, I'd like to hear why you enjoy it. I know a lot of people really love this game.

Thanks in advance!