Scene from Never Back Down 2 with Michael Jai White, talking about how anger is a detriment in combat:
Remember, I told you an angry mind is a narrow mind. Whenever you're angry you're only thinking about what you could do to somebody, you're not thinking about what can happen to you...
Isn't anger good for fighting?
No. It's about emotional content, not anger. (Concept borrowed from
Bruce Lee)
Does that anger make you work harder?
No it just makes you feel like you're working harder, you're actually burning out you mind. And where your mind goes you body follows. It's better to make your opponent angry so you can control the fight. The real test for you is for you to calm your mind.