Spot on Ben. Ditto ditto. +1
I too would like to treat others as I myself would wish to be treated. The attitude that "I will happily treat others the way I myself could bear to be treated without losing my rag." just doesn't cut it, in my opinion.
That said, I still feel like a learner in this field.
Especially important to step back from the situation and my immediate reaction to it, so I don't just stick my foot in my mouth. I once felt it necessary to write a rather clear email to my boss about something with which I disagreed. I poured out my unedited thoughts, then stopped, deleted the whole text and started over. Having got rid of the metaphorical bile, I found the second version to be completely different in tone and far more balanced. I edited it slightly, then hit send.
My boss' reaction was blunt and reactive, but after he had had a chance to consider it, he came back and apologized.
So yes, step back - the life you save may well be your own. The approach "if it feels right, do it" is incredibly bad advice in this context.