Self-attribution bias!

"We have a relatively fragile sense of self-esteem; one of the key mechanisms for protecting this self image is self-attribution bias. This is the tendency for good outcomes to be attributed to skill and bad outcomes to be attributed to sheer bad luck. This is one of the key limits to learning that investors are likely to encounter. This mechanism prevents us from recognizing mistakes as mistakes, and hence often prevents us from learning from those past errors."

Self-attribution bias!