Using idioms when talking to my advisor.

For example in my language there is an idiom "somebody broke the bank" which means that we've run out of something. So one day I told my advisor, that I can't start a new culture (some eucaryotic cells), because somebody broke the bank, meaning that there are no samples left in the big freezer. And she understood that somebody managed to literally break the liquid nitrogen cell bank. That was a loooong day for me.

Oh, and when your supervisor tell you to do something the fast way, by omitting some safety - don't do that. A friend of mine got poisoned with benzoic acid this way.