Facing this question in the GS General Games Discussion forum, I responded with:

I don't play games to "become" another character for a short period of time. I've never understood that mindset, but I don't think it's a bad one. For me there's something about playing games, especially really great games, that is hypnotic. There comes a point when you are so involved in what you're seeing and doing that your mind lets go of your troubles, however briefly, and your hands become an extension of your subcounscious mind. All of your goals are set out in front of you, there is no stress, and this new world is in the palm of your hand. You're not thinking about playing a game (or much of anything else) - you're just playing. That's the escape. That's what I play for.

It was the same when I used to skate. There would come a moment where all I had to do was think about doing my next trick, and my conscious mind stepped back to let my body be controlled as though I was dreaming. It was like falling asleep -- I only knew I'd been in "the zone" as I snapped back to reality and realized it was over. Everybody needs that "something" at least once in life, and for me right now, it's games.

I think I play games because... that's what I do (hobby-wise). Some people play poker, or trick out their cars or homes. Other people collect sports cards or collect CDs. I play and collect games. They say it's a waste of time. I say they're wasting time [that could be better spent playing games]. Go figure.