When you feel angry, it’s a good idea to ask yourself the question, ‘Why am I angry?’ If you sincerely seek for the answer, the reply will come: You expected something to happen the way you wanted.
When it didn’t happen that way you felt angry. So what is the cause of your anger? You are the cause.
You wanted it a certain way, and it didn’t happen that way. There is no way to blame somebody else as the cause of your anger.