Eat/Drink Like a Friggin' Adult

If you're 18 or older, there is no reason to chew with your mouth open, slurp when you drink, or eat while talking on the phone. 

Pick Up Your Damn Heels

If you can't walk in heels or boots without clip-clopping because you're too lazy to lift your f***ing feet, don't wear heels or boots.  While you might like drawing attention to yourself, others shouldn't be forced to hear your plodding.