World of Warcraft. The first game that taught me that who you play with can make a take a good game to the best game ever and then when those people quit playing back to just an ok game.
Leauge of Legends - Wished I would have put more time and become a professional, but you live and you learn.
DOTA - the original. First game I was able to play and enjoy online and with my brothers over dial up internet.
TF2 - playing with my brothers.
Baulders Gate 2 because stealing all the things was awesome.
My best friend's brother started a business selling WoW maxxed out accounts and even created an in game store sell custom clothes and weapons.
That's epic