Crab mentality, is a way of thinking best described by the phrase "if I can't have it, neither can you". The metaphor is derived from a pattern of behavior noted in crabs when they are trapped in a bucket. While any one crab could easily escape, its efforts will be undermined by others, ensuring the group's collective demise.
The analogy in human behavior is claimed to be that members of a group will attempt to reduce the self-confidence of any member who achieves success beyond the others, out of envy, resentment, spite, conspiracy, or competitive feelings, to halt their progress.
