I just thought of another, and this is a BIG weird one.
I have to say the interpretation first, cuz i dont think you'll get it, if i just say it.
In NY, for example...if we are waiting for a table at a restaurant, we say:
Do you want to look around the mall "in the mean time"
In PA, they say, "do you want to look around the mall awhile".
I HATE THAT ONE! i cant even explain why i hate it....the other weird sayings i dont hate...but this one, I HATE! haha