When you're an adult, you should have the capacity for introspection, the ability to examine your own emotions.
According to many theories of cognitive development, by the age of 25 you should have full ownership of your emotions, and you should understand that you choose how to respond in any situation. You should know that anger is a completely inappropriate response to any situation.
When you take ownership of your feelings, you know that you choose how you feel, unless, like me, you suffer from chronic anxiety disorder, then negative thoughts and feelings will play on the surface more frequently. But since I own my feelings, I know that what I perceive around me is through a lens slightly tinted with negativity.
You feel any way you choose to feel. Everyone chooses how they feel unless they have a neurological disorder. I may not be able to choose not to feel anxious most of the time, but I at lease understand that the feelings of anxiety are mine alone.
That means that feelings are not any other person's fault. Take the fight-or-flight response any way you like, but don't let your emotions cloud the situation and make you unnecessarily violent.