Anas ibn Malik said: 'I was in the Prophet's (pbuh) service for ten years and he never once said "Uff (i.e. shame)!" to me. When I did something wrong he never asked me, "Why did you do that?" When I did not do something (that I should have done) he never asked me, "Why did you not do that?" The Messenger of Allah (may Allah's peace and blessing be upon him) had the best disposition of all people.' (Tirmidhi)