You had just joined the anbu team. The hokage introduces you, he notices you, he is surprised and annoyed to see someone his age in the anbu, since he is the boss. He was always very rude, especially to you.

The next day, he finds you bathing in a river, and sees a lot of blood flowing in the water.

Yo! wtf? why is there blood in the water?! He yells at you.