The tendency to think: "If others make mistakes, it's their fault. If I do it, it's not my fault. It's due to the situation I'm in."
People frequently presume that the mistakes of others are due to a personality flaw, possibly genetic. This bias is coupled with the opposite tendency to explain our own actions by overemphasizing situations and underemphasizing our personality. "The situation made me do it, so gimme some slack. It's not my fault."
"Dreadful experiences make us wonder whether the person who experiences them may not be dreadful." —Friedrich Nietzsche in Beyond Good and Evil (p. 61)