What did you mean at first when you described "smashed a bunch of imposter syndrome"?

I have suggested to a friend that the feelings they were experiencing were a vein of imposter syndrome and the response I received was along the lines of, "I can't have imposter syndrome, in order to have imposter syndrome I would have to have done something worthwhile compared to others". Of course it comes from a person with Honours in Psychology and a concert pianist.

I just have a really big ego and can't relate. I am no imposter because I don't work like that. If I was in a room where I felt I was an imposter I would actually be an imposter - hanging out to gather all the secret-room insider-information I was trying to gather.

Can you describe the things that changed your imposter syndrome from "screaming at me about how I am not good enough" to "background noisy noise about things".