never thought about it quite this way before

Truman Capote wrote the following in his masterful, unforgettable In Cold Blood. I just had occasion to read the quotation and was struck by how much it reminded me of a man that I used to know well.

You are a man of extreme passion, a hungry man not quite sure where his appetite lies, a deeply frustrated man striving to project his individuality against a backdrop of rigid conformity. You exist in a half-world suspended between two super-structures, one self-expression and the other self-destruction. You are strong, but there is a flaw in your strength, and unless you learn to control it the flaw will prove stronger than your strength and defeat you. The flaw? Explosive emotional reaction out of all proportion to the occasion. Why? Why this unreasonable anger at the sight of others who are happy or content, this growing contempt for all people and the desire to hurt them? All right, you think they're fools, you despise them because their morals, their happiness is the source of your frustration and resentment. But these are dreadful enemies you carry within yourself--in time destructive as bullets. Mercifully, a bullet kills its victim. This other bacteria, permitted to age, does not kill a man but leaves in its wake the hulk of a creature torn and twisted; there is still fire within its being but it is kept alive by casting upon it faggots of scorn and hate. He may successfully accumulate, but he does not accumulate success, for he is his own enemy and is kept from truly enjoying his achievements.