I'm a bus driver, and I usually just let the very few passengers who work themselves up over nothing carry on as I know they'll exit the bus real soon, and then I'll most likely never see them again.
But sometimes, after a long day in rush traffic I feel that for my own sanity I need to end their tantrum. And that's why, when a passenger threw a tantrum about "the bus going the wrong way" when in fact they were on the wrong line I decided to tell them exactly that. "Ma'am, you are correct. Line 11 always turns left here, but this is line 22 and it always goes straight!"
I hoped she'd accept this and leave at the next stop. But alas, she kept on, going on a long rant about how this was the worst thing she had ever experienced.
I glanced at her and said "That makes you very lucky ma'am. I was stabbed once..." and then I just let that hang in the air as I watched her deflate as my words sunk in.
Maybe not very professional, but I must admit it felt good.