I went to a conference about anger over 10 years ago and something was said that really struck me. He said that if you have an orange in your hand, and you squeeze it, orange juice will come out. But that you can't get orange juice out of a lemon. In other words, if there is no anger inside you, then no matter how much circumstances squeeze you, the anger won't come out unless it's there already.
I have often asked myself that over the years since. "What am I angry about? Why is this particular child getting to me today? What unresolved anger do I have in my heart?"
Everything that happens to me can make me bitter or it can make me better. At this point I still feel that it's my choice. Maybe some day I'll get to the point where I don't feel I can choose anything but bitterness but for now I am still choosing to let what happens make me better.
But for now I'm holding to the Edwin Markham quote:
Defeat may serve as well as victory to shake the soul and let the glory out.