I have done demos in the past where the time flew by, because it was so busy. It isn't hard when it is a product you know and like, and people are interested in learning more about it. I wouldn't want to be assigned some new chip to put in paper cups, though. I've seen someone doing coffee pot demos in a department store and she was swamped! I'm sure her day goes by fast, but I also know she gets a ton of questions and has to know that product inside and out.
Former mystery shopper, current merchandiser.