This person is generally a good guy; friendly to newbies, or at least not hostile, contributes to discussions, and so on until one topic is brought up. When that one thing is brought to their attention, the Single Issue Wonk undergoes a frightening transformation, becoming an obsessed monomaniac who won't stop hammering their position. This may go on for days at a time, entangling unwary newbies and providing the perfect furnace for a Troll to dump fuel into. Compare Berserk Button. See also: Flame War and Misplaced Nationalism for the mess they tend to leave behind.