I guess I still find chess very interesting, but when I stopped I was around 1600, which is the stage where you really need to start using a computer to train and analyze your games if you want to get better, and I found that took a lot of the fun out of it. I also don't like the fact that because the best players all now train with computers, the level of play has soared (arguably a good thing), but has robbed us of the truly thrilling matches from earlier times, where people playing for the world title would make mistakes and then have to claw their way back. Now, the title matches are brilliant but boring, and I'd argue that players like Carlsen and Anand would not have done so well at such a young age had it not been for the computers.
As for arimaa, the game itself is not bad, it's just that -to put it in computer-game terms- it's just a chess-clone. It's not really unique, except for the randomized starting positions (for which you could just play 960 chess), and the different pieces.