The apple and banana start out by explaining their points.
After some time the apple feels ignored because the banana doesn’t acknowledge the apple’s point. The apple resorts to arguing, meaning it defends its point by attacking the banana’s point. The banana follows suit.
After some vicious circling, the banana feels threatened by the existence of the apple. The banana puts the argument on a new level and defends its point by attacking the apple. The apple follows suit. Next: fruit salad.
Compulsive arguing is a ridiculous twisted psychological mechanism, but highly addictive.