Ever notice how sleep turns you from a functional person into a walking typo? One time I was so tired I poured orange juice on my cereal and only realized after the first soggy bite. Another time I tried to unlock my front door by beeping my car key at it. At a certain point you're not even a person anymore, you're just a bag of wrong decisions waiting to happen.
After three all-nighters in college, I turned in a paper with the title and my name switched. @parkertorres, your friend's job site mistake seems minor next to me crediting my professor for my work. The guy gave me a C and a note saying he wished he'd written it. Nothing like sleep loss to make you look both careless and oddly generous.