This is something I have tried myself for dealing with bullies.
If someone makes unkind remarks, I say "are you having a bad day?" I may not mean it, at least to begin with, but if I say it and try to believe what I say, I can at least walk away feeling smug. I am on the moral high ground. I have behaved better than they did.
If you keep doing that, you may change how you feel about it and they may behave better.
If they react very badly, then just think it in future, rather than saying it.
It takes a lot of practice, but it made me feel differently about these people, at least some of the time.
You have nothing to lose by trying it.
