The peasantry sees anyone stronger than them as an enemy, unless you've crushed them, making them feel helpless, and they see you as master.
Envy is a hell of a drug.
Makes it so much of a hassle to cooperate with them it's not worth the effort.
More fun: peasants are unsophisticated, and go with [say mean things about enemies]. In other words if you're stronger than one and haven't conquered them recently, they will make up slurs about you endlessly until you do conquer them.