A chuckle: Tonight I was out at the local arcade (Gameworks Seattle) doing an initial survey for a small usability study. I made notes in a voice recorder rather than pen & paper, as it was more discreet. As I was walking out the frount door, preoccupied with thoughts of transcribing my notes, I (literally) ran into the quintessential Don Norman usability blunder: a nice big door with a nice big handle on which to grip and pull. The problem being that the door can't be pulled. Only pushed.
I tugged twice before laughing at myself and pushing out onto the street.