In martial arts, it is very important that the student respects his teacher. If the student-teacher relationship is not built on a solid foundation, resentment can build. For instance, you might just get tired of the old Sensei bossing you around all day, making you do push-ups when you’re tired, or make you constantly practice fancy taekwondo kicks that would be totally useless in a real fight.
However, the absolute worst is when your Sensei takes you to the mall on Saturday morning and has you do martial arts demonstrations for donations, then instead of using the money to buy some new gym equipment, he uses it to buy World of Warcraft’s Wrath of the Lich King expansion pack. Hate it when that happens… old bastard.