...and then there was this:

Me: ...nice to meet you. Let me know if there's anything else I can get you this evening
Customer: can you find me an 8-ball?
Me: no sir, and I'm probably the last person you should ask
Customer: oh that's too bad, you could make a killing
Me: you're probably right, sir. However, I like jobs that don't have the risk of putting me in jail
Customer: you're doing it wrong