3. Left 4 Dead
Picture this scenario: You inhale some of God's greenery and then decide to head online to play Left 4 Dead (Or any shooter of your choice.) You make a few mistakes here and there due to slowed muscle memory and before you know it you are being berated by eleven year olds. Yes, ELEVEN YEAR OLDS. The next morning, you won't be able to look yourself in the mirror.
If you don't mind getting played by little kids at least stick to Mario Kart where you won't be able to hear their pre-pubescent jeers.