From: Aline Lerner (edited)
People can't tell how well they do in interviews. Some think they did poorly when, in fact, they did well.
When candidates think they failed the interview, they are less likely to want to work with you.
First they self-flagellate, then they soften the pain by rationalizing that they didn’t want to work in your company anyway.
If you want to save these candidates, give positive feedback immediately (or as soon as possible).