Fight, flight, and freeze. The three reactions an animal could have when confronted with danger. Freeze was the least optimal of the three, and was often ignored for the much more concise phrase, 'fight or flight.' After all, in most cases the animal that froze was the one that ended up killed and eaten.
Evolutionarily speaking, with the exception of a few creatures that had good camouflage skills, freezing was considered a bad reaction.
