It may sound callous, but I've learned to mock them back. Now, when someone does something nasty to me, I laugh at them for being so small. I get a real kick that my little action set him/her into a tailspin. At first I was uncomfortable doing it because I was a 'nice person' and thought it was bad to change and I didn't want to be seen as a b**ch, but now it feels healing to brush it off. For instance, someone cuts me off in traffic and starts flipping me the bird and yelling. I laugh and shake my head and their reaction goes from anger to becoming unsettled by my reaction. Bullies get difused when you look them in the eye like they are an idiot. Of course, it doesn't always work, but it works better than having myself hunker down and feel miserable. It takes practice to do this because it goes against a person's good nature, but don't be alarmed because you remain a good person. Let their issues remain as their issues and don't absorb them as yours.