People suppose [aggression] to be more dangerous than fear, but this may well be a mistake. Nor is aggression--as Freud thought--essentially destructive. For instance, disputes are aggressive, but they are not attempts to destroy one's opponent. And children's play, which has a strong element of controlled aggression is certainly not destructive. There are not (as used to be supposed) any non-aggressive human societies. Opposition is an essential element in human life: aggression is part of the emotional equipement for making it work. Societies which keep it within reasonable bounds (unlike our own) are doing something much harder and more interesting than merely never feeling it in the first place.
Mary Midgley, Wickedness. Routledge (New York: 1984) p. 92. The children's play point, while concisely giving an extraordimarily important argument, should surely be qualified slightly, e.g., "is generally not destructive" or "is not necessarily destructive".