I once had a lady at a craft sale with a little girl - the girl was looking at one of my comp books and wanted to buy it. The mom told her that it was just a notebook with some paper slapped to it. I heard her and said, well yes but I slapped it on in a very nice way! The mom was shocked that I had heard (well she said it right in front of me) and started to say something, but I wouldn't let her finish. I just gave the girl the notebook because she was sweet and she really liked it and the mom ticked me off. But that really was the only nasty type comment I have had.
I have had people say "oh I could make that" but most times there is someone with them who responds "your house is full of boxes of stuff that you thought you'd make, just buy the thing already". I always laugh at those people.