I sometimes hear my Mom's voice in my mind. A friend was very mean and I was upset by it. I heard my Mom's voice say, "It doesn't matter what she did; it only matters what you do."
How true this is. We cannot control what others do. We can only control what we do or how we react. Still, meanness in any form always makes me sad, especially when it comes from someone who is supposed to be a friend. I'm not mean back but I do withdraw as much as possible to remove myself from exposure to such toxic behavior.