From LoL: One does not simply gank Kayle.
I actually call this one out in-game after the enemy fails to gank me. My Kayle build can 1v1 pretty much any champion in the game (so long as they're not indcredifed) after level 10 or so. It's funny how many people love to impale themselves on my sword.
I've also started a "one does not simply chase Thresh" recently, because rarely does anyone survive that when I'm Thresh.
Otherwise:
One does not simply beat a level in Fire Emblem on the first try.
One does not simply play online with Steam running (DOTA2 and TF2 ALWAYS update when I do)
One does not simply use the Wii (between uses there's usually a power surge that takes it out, requiring a 10 minute or so reset before I can use it)