first customer:

Pull down your pants and say "when you kiss my ass, you will get a "your welcome""

Second customer:

while retrieving book, pull down entire shelve of books on her, while she is knocked silly stomp on her head. Blame it on some neo-Nazis that walked by.

Third Customer:

Reply, "well in Canada they have men with huge cocks, so I guess you are the reason why we don't have the paperbacks here."