I was hurt. I still am if you want to know the truth, especially because this someone should know better. But no one will die over this. Probably no one will lose sleep. In the grand scheme of life, it's probably just a speck. Not even everyone affected by it will know about it.
But I know and I'm kind of stung. Sometimes things happen that are out of your control. That's when you want to know someone has got your back. And sometimes you learn that they don't and you find yourself adrift.
But you know what? That floating out there on the stinging raft led me to look at another situation in my life. A situation where I've been the not-so-nice one. Oh, I had reasons. But those reasons probably don't matter to the person that I've stung. Maybe that person doesn't even realize what I've done. Or maybe they do. But I know. And I know better, so now I have to do better.
The moral of the story is: 1. Treat people the way you want to be treated and 2. when you realize you've failed to do that, go back to number 1 and start over.