You work in office A,you've only been working there for a few months, you make a mistake at work, then your boss calls you to his office.

As long as you work in office A, you don't even know who your boss is, now you going to to your boss's room, you knock on the door, "Sir, are you calling me?"

"enter." said your boss, then you entered your boss's room, and to your surprise your boss turned out to be your former bully when you were at school!