We are motivated/concerned about lack more than what we have. So if you constantly criticize someone/others for imperfect, suboptimal behaviour, you are likely

We are motivated/concerned about lack more than what we have. So if you constantly criticize someone/others for imperfect, suboptimal behaviour, you are likely to criticize yourself too. Just paint the world with broad brush once a while, so that you calibrate away from cynicism and fault finding.