Either frustrated/angry or happy. These were the only states of mind I had a few years ago. Transitioning between these was a quick process, only a few triggers were required.
One's anger is one's enemy and one's peace is one's protection - Baddena Bhupaludu
This was the line that converted me into an "Imperturbable" (even I had to google it).
Whenever I have an urge to shout or get mad due to unfavorable stimuli, a middleware runs, asking questions to the logical part of my brain: "is it a right time/place/situation/person/matter to get mad?", "what are repercussions of my madness episode?", "am I being right by picking a fight?", etc.
By being like this, I get to enjoy a lot of benefits like not getting a stupid argument ruin my day or cost my job, just by simply letting go your ego to win one. But this nature has a few drawbacks too. People think you are too weak or scared to pick a fight over a good cause.
My answer, you don't need to use violent or aggressive methods to accomplish truth or justice.
Conclusion: Rise over your emotions. Be composed. Trust your logics instead of emotions/guts.