Musnad Ahmad 32:1078

Hajjaj narrated to us, Sulayman narrated to us, from Thabit, from Anas, who said: "I served the Messenger of Allah (peace and blessings of Allah be upon him) for ten years, and not every affair of mine was as my companion would have liked it to be. He never said 'Uff' to me regarding anything, nor did he say to me: 'Why did you do this?' or 'Why did you not do this?'"