We are all shitheads.
Why? Well, first of all...because we can't believe that we can make mistakes. This is the ego problem. The shithead is always somebody else. Except that it isn't, because while we're so busy blaming other people, we fail to recognise our own failings.
So, I'm a shithead, you're a shithead, everyone you know is a shithead. At some point, we will all make a mistake. If we recognise when this happens and learn from it, we become stronger. If we deny it, then the world just accumulates more shit. Other people will look at our shit and learn from our example; that shit isn't bad, it doesn't hurt us, and we can get away with it.
Of course, shit is bad, shit does hurt us, we can't always get away with it, and in fact we should never let ourselves get away with it.
"You can never be careful enough."