" Take another bong hit"
"Wuz uppppppp"
Both of these really bug me, but my all time most HATED which has just started where I live,
"Have a blessed day"
This one really bug's the holy hell, (pun intended) out of me. I normally reply in return with something like " have a cursed day " just to see the look on peoples face, or I will say something like "why thank you father" or "sister" as appropriate, the look on these people mainly store clerks is amazing.
Todd