This may all be a matter of different nuances on words like "embarrassment" and "shame", but personally, I would put higher trust in someone who firstly recogni

This may all be a matter of different nuances on words like "embarrassment" and "shame", but personally, I would put higher trust in someone who firstly recognizes that they could have done better and secondly regrets that they did not, and I would prefer to be that way myself, without being rendered ineffective by it. One can never, however, be sure that someone really feels that way ("The secret to success is sincerity - once you can fake that, you've got it made!") Nevertheless, faking it involves never saying certain things, and that turns out to be hard, so the fallible approach that I aspire to is to assume sincerity unless given evidence to the contrary. In this view, blameless postmortems are the right way to go, at least up to a point: neither embarrassment nor regret are things that can truly be imposed from outside, and definitely not sincerity.