I so wish I could take credit for the gag here, I really do. But no, this one was taken from a true story - I was browsing the "Mock the Stupid" LJ community and came across this hysterical story of an idiot customer. Since I've already established that some of Our Heroes work at a restaurant, it wasn't hard to work in.
Thanks to Adam for letting me use the story in the first place - it was just too good not to immortalize further. :)