Some years ago, when I was working as a waiter, the restaurant celebrated Halloween by having all of us waitri dress up. I got to the costume shop late, and all they had left was a hippie outfit.
So, the next day, I'm waiting tables as a hippie. And I start playing around with it. As in, walking up to my tables -- after I've served them drinks -- and saying stupid stuff like, "Hey, brothers and sisters! I lost a couple hits of acid when I was fixing your drinks. Could I sip your cokes in case I accidentally dropped my hits into them? It really bums me those hits might go to waste."
Most people got that it was a joke. However, there was this table of church folk that took me seriously. I can still see their faces! Such shock!