Sahih Bukhari
Good Manners and Form (Al-Adab)
Volume: 008 / Book Number: 073 / Hadith Number: 64
Narrated Anas:
I served the Prophet for ten years, and he never said to me, "Uf" (a minor harsh word denoting impatience) and never blamed me by saying, "Why did you do so or why didn't you do so?"