I was a CM for awhile, and I heard it all. Here are just a couple of my favorites:
1) I was working the door at Innoventions when a summer thunderstorm popped up. We would always draw a massive crowd of annoyed people at those times, so I always went out of my way to try to cheer them up. But one woman was beyond hopeless:
Woman: Excuse me, miss. Can you go tell them to turn off the rain?
Me: I'm sorry, what?
Woman: Go tell those people to turn off that rain! I paid a lot of money to get in here, and I don't know why you think it's funny to get me all wet!
Me: I do apologize, ma'am, but I'm sure it won't last long. Here in Florida it rains almost every afternoon during the summer, but it clears up quickly. I'll be happy to contact our weather department and find out what time it will end.
Woman (now screaming): Apparently you don't understand me! I know how all your little tricks work. Ha ha, real funny! Now get hold of the person in charge and tell him to turn off the d**n rain!
Me (into my radio): Um, God? This is Innoventions Greeter. Could you please turn off the rain?
**A few seconds pass**
Me: I'm sorry, ma'am. He doesn't seem to be by the radio right now.
Woman: Oh well. Thanks for trying. Have a good day now!
2) My own father did this one. We were at Fort Wilderness for a few days, and for some reason we ran into every single surly, grumpy CM in the place. We've stayed there since and never had a problem, but this was just one of those trips. So by the last day, he'd had enough. We went to the front desk to complain to a supervisor.
(Dad finishes up the rather long story)
Supervisor: I'm so sorry that happened. I know you mentioned the CM's names...do you happen to know their last names?
Dad (frustrated): Last names? You people don't have last names! It's just "Hi, I'm Bob." "Hi, I'm George." (in a perfect Mickey Mouse voice) "Hi, I'm Mickey. Heehee!"
That was it. My boyfriend, my mom, the supervisor and I were all on the floor.

I don't even remember what the supervisor did to make it right, though I'm sure he did something. But to this day, whenever we run into a grumpy CM, one of us will spout off "Hi, I'm Mickey. Heehee!"
I have a bunch of others, but those are my favorites.