You can quickly get a "bloody nose." Mainly in a figurative sense, since most of us don't usually step into a real boxing ring. But everyday life is often hurtful enough that some people might wish to risk a bloody nose in personal situations rather than everything else that can happen to them.
What hurts much more is a blow to the soul. When we are hurt emotionally, the pain is often greater and more dramatic than a real punch in the ribs. So it makes perfect sense to study more than just pure self-defence. The psyche must be trained and strong enough. The solution is courage.

