How to overcome "it's not fair?"

Every person has their own "good" and "bad" lines. Every one. It may be very different for each person. What I consider "bad" behavior may not be universally bad, but that doesn't negate my feelings.

Not negate them perhaps, but I would think it could help put them in perspective and ease the bad feelings towards others up some. The idea of no universal is more for the proposed do-gooder's benefit than for those of whom they disapprove.

I obviously don't subscribe to moral nihilism.

Sorry for the hijack scorp!

You are asking how to regulate and/or manage emotions.

There are many tools in Dialectical Behavior Therapy for this purpose.

For example: you can intentionally act in the opposite direction than that towards which the emotion is pushing you.

You can distract yourself from the emotion.

You can observe, be mindful of the emotion and anticipate that it will pass.

DBT Lessons