I've had to adopt the "couldn't care less" approach when someone directs what I feel to be an unsubstantiated claim in my direction.

Of course when the moment has passed, I'll mull over it if the person is usually friendly and then work through the claim like a detached third party to figure out how I should really feel/think about or act on what they said.

It's the only approach that has successfully worked to keep my feelings from obliterating my psyche for the rest of the day/week if a confrontation like that does happen.

I keep them insulated and examine them later.