1. Fun.
2. Interaction with the community.
3. Customization.
4. Cost.
5.
Because in real like, running around in elven armor with a bow, shooting wolves in the face, and having sword fights with marauding bandits isn't easy to do. And you can't have as many personalities as you want, or save your game so you can reload when you die. :(
5 things that don't matter when I play a game.
1. Graphics. Although some use of color would be nice.
2. Realism. After all, I thought I was playing a game.
For 1 and 2, if I wanted real life graphics and super duper realism, I would go outside. Rather than waste power by using a console/computer.
3. Unlockables. Infact, sometimes I wish there were none. I can get them easily, but while you're sitting there doing things you don't care about to get these, you eventually get bored by the time you actually get everything, then after that you don't play for long.
4. Reviews and ratings. I don't give a stuff if someone gave it a 2/5. If I find the game fun, then I'll play it.
5. Prequels. So what if number 2 was better? Doesn't make number 3 terrible. It's still fun and I'll still play it.