While pruning the mistletoe out of a huge water oak in the middle of January(they're deciduous, BTW), the owner's son came over and started yelling at us for removing all of the live limbs and leaving just the dead ones in the tree. All I said was, "You're joking, right?" Unfortunately, he was serious. I didn't even try to explain it to him, just kept on working.
One of my favorites: "What can I do to keep all those leaves off my roof?" Ummm, buy a blower?
Or, after watching you prune the entire tree, telling you how great it looks, then watching while you clean up all the gear, rake up, blow off, and load up the truck, they ask, "Aren't you gonna get that limb over the roof?" ARRRRRRRRGGG.