The worst one was when my (straight-haired) friend was telling me about her new hairbrush that she'd bought, and telling me that I should try it. I said something along the lines of; 'I don't brush my hair at all so there isn't really much point because it makes it frizzy.'
She then said something like 'Well that's probably because you're using a cheap brush, if you used a good brush then...'
If all it would have taken for me to beat frizz was a hairbrush, then didn't she think I would have done it years ago? Ignorant.