It wasn't anxiety as much as knowing that if I faltered even a little that this particularly interviewer would say no. I had not written fizz buzz in a few years and decided that the fact I thought about it for a few seconds meant I had already thrown the interview away.

Im just saying its thanks to my instinct that I have been so successful in my life, and I have never lost anything by refusing fizz buzz, yet have attained good things.

Maybe its survivorship bias.

It goes against my rules to proceed in interviews I think don't lend themselves to the situation.