When did affairs, drug use, and deliberate acts become "mistakes"?

Folks excuse all kinds of smy behavior by merely calling the acts mistakes. They aren't mistakes- they are deliberate, considered acts. People don't "mistakenly" engage in long term affairs, take drugs, or drink every day by "mistake". The acts are commited on purpose. You stub your toe by mistake. You lock yourself out of your car by mistake. You forget to set your alarm by mistake. You DON'T mistakenly get in bed with somebody, drink like a fish, or have cyber affairs. Are smy acts different IF they are called mistakes? Why do we lie about what the acts really are?