Let go
Think about the most unpleasant relationship you have ever had. Maybe it was a coworker, former spouse, or a rebellious child. Did you ever catch yourself keeping a mental count of all the times they had hurt or disappointed you? I have found that there is great virtue in not counting but instead letting go.
Think about it. What besides an ulcer do you gain from keeping track of all that bad stuff? Maybe a migraine headache? Most bad things others do to us, from something stupid to something deliberate and calculated, are best handled when we let go.
