Effects of minecraft on the brain?

I recently downloaded minecraft for my PS3 and iTouch, it's so much fun and i can't put it down! It's so much more fun than COD or Boyfriend or NCAA! I love it it's awesome… That's what I thought until things got a little funky. I would play it alot than as i would close my eyes i would start building stuff in my head it got really annoying and creepy. In class today I kept sneaking on my iTouch to check out my world and when I'd read I 'd see the story in pixels. It started to bug me and creep me out what are some positive and negitive effects of mine craft on the brain?
I thought of a couple positive and negitive effects
positve
1. Builds Imagination

Negitve

1. You start to see blocks

2. You think your in the game

3. You can't put it down

what are the effects positive and negitive please don't troll be serious c'mon how old are we?

Anything that you play/practice for long periods of time start to take it's toll on you mentally eg. Play tetris for long periods of time and you will start to see tetris blocks when you close your eyes or practice a musical instrument for long periods of time and you will start to think of the different sounds each key makes. This happens because you become so obsessed with something that it becomes the #1 priority in your thought process. My advice is "everything in moderation" ie. Don't play Minecraft so much, take a break and do something else that will keep you occupied for awhile. Ps. Those effects can be positive/negative depending on how you feel about it.