The following scenario can be applied to determine the stupid people in all service industries:
Customer: Do you have any __________?
Service Provider: No. I'm sorry, we 're sold out/it's unavailable/we don't carry that.
Customer: Well, do you have any suggestions?
Service Provider: Yeah, dumbass*. Plan ahead or go somewhere else.
*Note: the phrase "dumbass" is merely a suggestion. Other appropriate monikors may include: douchebag, asshole, numb-nuts, whore, or the ever-appropriate (yet dripping in sarcasm and loathing) sir/maam.
"I became insane with horrible periods of Sanity"--E.A. Poe
www.wncc.edu/~heath/