Good Manners and Form (Al-Adab)
حَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ، سَمِعَ سَلاَّمَ بْنَ مِسْكِينٍ، قَالَ سَمِعْتُ ثَابِتًا، يَقُولُ حَدَّثَنَا أَنَسٌ ـ رضى الله عنه ـ قَالَ خَدَمْتُ النَّبِيَّ صلى الله عليه وسلم عَشْرَ سِنِينَ، فَمَا قَالَ لِي أُفٍّ. وَلاَ لِمَ صَنَعْتَ وَلاَ أَلاَّ صَنَعْتَ.Narrated Anas:I served the Prophet (ﷺ) 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?
From Sahih al-Bukhari, whose reports the scholars accept as authentic.