Confessions of a Caveman Mandarin Speaker: "不用说了"

I think I was one of the people Ken Carroll referred to when he said certain people show up in China and start saying inappropriate things.

I was informed today that saying "bu2 yong4 shuo1 le " (needless to say) in response to a compliment is considered rude. I thought I was being polite. I don't know how I grabbed this particular phrase, but it came out and seemed right at the time (and unfortunately kept using).

I think I'll stick with "guo4 jiang3" 过奖 or something similar in the future.

I have more mistakes to confess, some worse than above, some on the funny side.

I'm sure there are others that need to confess. Any other stories out there?