Make no friendship with a man given to anger, nor go with a wrathful man, lest you learn his ways and entangle yourself in a snare.
-Proverbs 22:24-25

The king says that we must not befriend those who are "given to anger." Ideally, the hotheaded, hair-trigger tempered guy would have no friends. Best case scenario, everyone avoids him because he's destructive and unpleasable, and teaches others to do the same. The hope is that perhaps his lonesomeness will lead him to a change of heart.

Thank God that happened to me by the way, I used to be that angry guy when I was a teenager. I ended up with no friends and through a long period of isolation learned to quit processing everything through a lens of "what makes me angry today?"