I hate it when magicians think that they know everything after dabbling in magic for a year or two. I've been swimming in magic for about 25 years now. I've worked with the best in the business, I still get stumped and I still get fooled often.
I hate it when my audiences wont relax for just a moment and let me have control. I'll pull out a brand new effect that either I learned from the creator or created myself and every once in a while I get a few people in the crowd saying "Oh, I know this one!" This happened at a carnival I was working over the weekend. I brought out a rubber band and a washer and a random 12 year old kid immediately said, "Oh, I know this one!" Come on! I just want to say, "Relax, I'm going to do some stuff here that you will not understand. It will be fun." After I did the trick he insisted he knew how to do the trick, he even tried to explain it to me. He was dead wrong. We talked afterwards and everything was okay, he was just hard pressed to make sure that everyone knew he was a know it all. That ruins it for everyone.
I can't stand it when magicians ask how a trick works. There's some stuff you don't get to know! Be happy that there is still stuff out there that fools you