Using large, difficult words that most people will not understand. Makes you look like an elitist prick that wants to flaunt your advanced intelligence or vocabulary.
"So I told the rather rubicund fellow that I would not forbear his facetious predilection, and that I would extirpate him if he persisted. However I refrained from the notion because I desiderated copulation with his girlfriend."
Said without ten-dollar words:
"So I told the red-faced bastard that I wasn't gonna put up with his sarcastic attitude, and I was gonna kill 'em if he didn't stop. But I decided not to 'cuz I wanted to bang his girlfriend.