Off the top of my head, the use of the word 'good' in specific phrases like,
"How did you do on the test?"
"Oh, I did good."
Oh, you did, did you? Well, if you're above 4 years old you sound mentally suspect. How do you announce it's lunch time, "Me hungry??" (I know it's a complicated situation with 'good' and 'well' and whatnot; this is the only use of it that drives me nuts).
Also substituting 'what' for 'which.' One conversation I overheard in high school stands out, "yo, what girl is that?" or the very precise inquiry as to the specifications of a composite hockey stick, "[derr] what flex?"
People who bring their kids into bars. What the fuck? I don't want to swear around kids, but censoring myself after a few drinks isn't the easiest, especially given my proclivity to drop the f bomb a lot in that state. Your world, not THE world, revolves around kids, get over yourselves.
*feverishly checks post for ironic grammatical errors*