I am interested in collecting examples of pleasant surprises in interaction design--primarily screen-based, but not exclusively.
An example would be when I was trying to figure out how to increase font size on my daughter's Kindle touch. I tried pinch-out and it opened the font size controls.
Another way to think of this is based upon prediction and expectation--when we expect an interface to behave a certain way and it does, we feel good about it. When it doesn't, we can experience anxiety. I am looking for examples where the interaction does not go as we expect but the result is pleasure--not anxiety.