Here's a few customer story types that sound a lot more interesting in your head than they will coming out of your mouth:
People who order something you don't have and are very insistent about it. This happens at every job. People try to order spaghetti from a McDonald's, Xboxes from an Apple store, Camrys from a Christian bookstore, or cats from a ... I don't know, auto parts wholesaler. This is probably more worthwhile as a group game where everyone quickly names the weirdest item a customer has tried to buy from them and the weirdest one wins, and less as a long monologue where everyone already knows the entire story except the item name.
"No, ma'am, I don't believe we have a 747."
People who ask about something it is your job to tell them about. Look up any collection of "dumb customer stories" and you will always find one guy "LOLing" at customers who called a computer help line because they didn't know how to use their computer, or who asked a store employee where to find something in the store. These things are obvious to the employee because the company specifically chose/trained employees to know these things, and they want employees trained in such things so that they can give the information to customers who do not know these things. I can't believe I had to write that sentence, but if people keep telling stories about "idiots" that didn't know the difference between 802.11g and 802.11n or dared ask them where to find the nonfiction section when everyone knows it's in the back right corner, then I guess it's got to be said.