Deliberate mistake: When all the thumbs are at the wall saying "I'm the king of the globe" and "I'm a dentist" you cannot see their legs, so that saved some costume work.
Deliberate mistake: Throughout the whole short film, Geri's hair doesn't move or react to anything (such as the wind or his glasses). The glasses even seem to go through his hair without any movement in his hair. (00:01:00 - 00:03:35)