Tokugawa always has those juicy bananas and other wonderful resources and is unwilling to share them. I hate him for that. Montezuma is also very annoying, even though he's ultimately pretty harmless. If he's on the same continent as me, I'll eventually have to wipe him out, or at least batter him into obscurity, before I can have some peace. Mansa Musa is a nice guy who will trade technology even when no one else will, but he's a severe threat in space race and I don't like spaceship victory much. That makes him somewhat annoying.