RCMP Humour (a personal story)

Dan and I went to Crescent Beach for dinner tonight. We brought along a nice picnic dinner, had a bit of ice tea, took a few wierdo pictures and went home. But before we could leave the parking lot, a female RCMP officer motioned for me to pull over. I wasn't really panicked, but was wondering how i was going to explain why I was driving a car belonging to a man named Matt Kok. BUt i played it cool, knowing i had done nothing wrong, and pulled over. The conversation went as followed:
RCMP: Good evening. Can i see your driver;s licence please?
(i fumble to retreive it and hand it over)
RCMP: Have you had anything to drink tonight?
Amanda: NO.
RCMP: HOw was it out on the beach today?
Amanda: Oh, we just came for dinner.
RCMP: What did you have?
Amanda: Tacos!
Dan: With no cheese.
RCMP: YUm!
Amanda: Yah, i forgot the cheese.
RCMP: That'll bum you up. Have a good evening.

A small amount of shocked silence, followed by giggles. "that'll bum you up!" WHo says that? (i know, i would, but what part of a respectable society says that? Apparently there are people who share my kinda humour.