Why do you play WoW?

[Tearyn]

I find the raiding fun while its progression, and my guild is an awesome group of people that keeps the game worthwhile when its farm content.
Used to enjoy the PvP up until cataclysm, hopefully will again in WoD.

[Tuor]

Or is it to relax after a stressful day of work?

For me, as you've said above, is mostly a a way to relax from stress. It doesn't matter if it is work related or not.

That is why i loved so much the wrath system, it suited me so much better then the current one.

[Ciddy]

To immerse myself in another world after a stressful day.

This. Same reason I play most games these days: to get away from reality for a while.

[Itisamuh]

I play because I can never get my friends to play anything else. But as a general rule I play games to immerse myself in more interesting worlds.