My favorite was from a guy that came to my table at the convention (come to find out: he was also selling soap, and wondering why his weren't moving, and someone pointed him to my table ~_~).
"What is all this?"
I start my friendly spiel. "It's soap ^_^ Hot process, and glycerin, and--"
He cuts me off. "I KNOW THAT, I'm a soapmaker too."
"Oh, how lovely! I--"
"What's hot process?"
I was a bit bemused to say the least. Why ask a question you know the answer to?
I also got a lot of 'is it fudge?' I had signs up saying that it's not food, don't eat, etc etc, and someone STILL bought a bar and started to eat it. I found this out from a friend that saw the guy walking, unwrapping, and taking a biiiiiiiiiiiiiig bite. I think he was too embarrassed to say anything or come back.
And the amount of 'I need a NATURAL soap without lye in it' made me roll my eyes so hard I was afraid they'd fall out.