There are many things, for example, becoming morbidly obese and dying of a heart attack in your 20's, getting convicted of a violent crime and being sentenced to life imprisonment, getting killed in a war, getting killed in a car wreck.

Humans are not rational brains riding round in a sort of meat carriage, we are animals and our whole body (and social setting) adds up to who we are. Physical conflict is part of human life - specifically a proportion of young men are predisposed to physical rivalry. Taking options to express this away does not remove the predisposition, it merely shifts it to other outlets which may be much less constrained and much less positive.