People roll out either depending on the situation. It is hand waving, not reasoning. IOW, you can explain anything away by taking one of the two sides of this a

People roll out either depending on the situation. It is hand waving, not reasoning. IOW, you can explain anything away by taking one of the two sides of this argument. "You think you are good? Ha, no, dunning. Oh, you are not sure you are good? Ha, wrong, you must be great" type stuff. While these effects exist in large populations, you can't really use them to reason about any specific instance.