When you're blocked by association (just for being friends with someone) but weren't involved in a disagreement, how do you make yourself feel better?

That has happened to me before. Thinking it through helps. Initially it does feel like something against me, but when you think about how upset that person must get just because they see someone who is friendly with someone they don’t like, I end up feeling sorry for them.
I know how upsetting small things can be to myself, and I feel lucky things like that don’t bother me.