The link below is from one of my favorite sites, Cracked.com, but I’m afraid they left one out that should have definitely made the list…
Customer—Where’s the (any item easily found)?
Me–Actually, it’s right (next to)(behind)(in front of) you.
Customer—Oh, if it was a snake, it would have bitten me!!
Voice in my head–If it was a snake, I would have let him!