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He's a fountain of misplaced rage. Name your cliche; Mother held him too much or not enough, last picked at kickball, late night sneaky uncle, whatever. Now he's so angry that moments of levity actually cause him pain; give him headaches. Happiness, for that gentleman, hurts.
— Garland Greene · Con Air

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker lists familiar explanations for a man’s anger, ranging from parenting and childhood humiliation to possible abuse by a relative. The dismissive catalogue gives way to the main accusation: rage now dominates him so completely that even other people’s happiness and lightheartedness seem painful.
Context reviewed