To escape from the cruel reality I live in. In all seriousness whenever my mind is way to stressed out and filled with thoughts a nice gaming sessions helps me cool down. It makes me feel a lot better and more relaxed after a good gaming session.
Usually about an hour or two a day. When life isn't busy I usually got 4-5 hour sessions. It does help me when I'm feeling a bit down. I enjoy the escapism.
Depends on the game like others have said. If it's a game of Dota and I want to do ranked games, I would group up with friends. Sometimes I'll play solo games but I'll get frustrated in the end with the random teammates I end up with.
Although if it's a local co op game, nothing beats sitting...
My cousin gave me his Super Nintendo. Super Mario World was the first game my parents bought me and my brother. It was fun playing through the game and finding all the secret exits and levels.
Has to be to the Gamecube for me. My brother and I logged so many hours playing each other. I ended up losing most of the time and went through several controllers. But, it was a fun time.