People playing air instruments
Human beat boxes
White people in dreadlocks
Capoeira (esp when performed on the dancefloor)
Tatooed logos (including band logos) and people who name their children after brands (yes, I read Julius Caesar)
When people quote lines from movies (excluding Scarface)
Manufactured sexy personas
Children who speak French.
People blowing their burps to one side
Pets named after Tolkien characters
People who tell you to 'smile!'
Anyone, for that matter, who comments on my smile.
Newly-acquired slang used without irony.