In a class, a large gentleman opined that folks don't mess with him because of his side. Using a training knife, the small teacher basically 'eviscerated' him.
Oops -
I was also an expert witness in a case. Two gentlemen had an interaction over a road incident. The large young man advanced on the older skinny man to use his skill at fisticuffs. The old man took a paring knife (little thing) out of his pocket and stuck it into the young fist fighter -who proceeded to drop stone cold dead from a magic sweet spot hit.
That's why distance is your friend. Fist fists are last resorts and to be avoided.