1. Your feelings typically say more about yourself than about another person. Use them for self reflection.
2. Feeling wronged when someone is an asshole is just. Learn to create boundaries and find ways to separate yourself from such people, both physically and emotionally.
3. Very few things are made better by being obsessively angry. Learn what is causing your anger, work through it and confront people you want to keep a relationship with.
Most of all, try to always give others the benefit of the doubt, and if they ask forgiveness grant it. If they prove themselves repeatedly unreliable than form the appropriate boundaries, but still treat them with the respect that any person deserves.
"When someone hurts you, be hurt."
This is not the way. Instead, be tough and say, nothing can hurt me.[1]
[1] https://dictionary.cambridge.org/us/dictionary/english/stick...
I've never seen taking offense the same way since hearing that.
Your comment is a loaded straw man, and you've confused being offensive and taking offense as a single event when it is two separate and distinct events. I never said anything about fault. I only referred to responsibility. Ultimately, we are each responsible for our own actions. Taking offense is an action. Even if an individual's emotional response is involuntary, that individual alone is responsible for their emotion.
I can tell you that being thin-skinned is just as much a symptom of mental illness as being offensive, and they usually go hand-in-hand: the most offensive individuals are usually also the most overly sensitive individuals.
It may be the case that some of us can choose whether or not to be offended in any kind of circumstance, but that doesn’t prove everybody can, just like many people not simply being able to think themselves out of major clinical depression. It would be strange to blame them for this.
Edit: grammar