The pratfall effect

french paper

The pratfall effect is a psychological phenomenon whereby the attractiveness of a person perceived as competent increases if the person commits a blunder. Conversely, the attractiveness of a person perceived as incompetent decreases if the person commits a blunder.

Wikipedia

....an experiment by Kay Deaux demonstrates that the pratfall effect applies most strongly to males. She found that, although most males in her study preferred the highly competent man who committed a blunder, women showed a tendency to prefer the highly competent nonblunderer, regardless of whether the stimulus person was male or female. Similarly, my colleagues and I found that males with a moderate degree of self-esteem are most likely to prefer the highly competent person who commits a blunder, while males with low self-esteem (who apparently feel little competitiveness with the stimulus person) prefer the highly competent person who doesn't blunder. It should be emphasized that no sizable proportion of people-regardless of their own level of self-esteem-preferred the mediocre person.

Elliot Aronson The Social Animal [via here - link contains a longer account of the original experiment]