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?"  

خَدَمْتُ النَّبِيَّ ﷺ عَشْرَ سِنِينَ فَمَا قَالَ لِي أُفٍّ وَلاَ لِمَ صَنَعْتَ وَلاَ أَلاَّ صَنَعْتَ  

Anas said, "When Messenger of Allah ﷺ arrived at Medina, Abu Talha took hold of my hand and brought me to Messenger of Allah ﷺ and said, "O Messenger of Allah ﷺ! Anas is an intelligent boy, so let him serve you." Anas added, "So I served the Prophet ﷺ L at home and on journeys; by Allah, he never said to me for anything which I did: Why have you done this like this or, for anything which I did not do: 'Why have you not done this like this?"  

لَمَّا قَدِمَ رَسُولُ اللَّهِ ﷺ الْمَدِينَةَ أَخَذَ أَبُو طَلْحَةَ بِيَدِي فَانْطَلَقَ بِي إِلَى رَسُولِ اللَّهِ ﷺ فَقَالَ يَا رَسُولَ اللَّهِ إِنَّ أَنَسًا غُلاَمٌ كَيِّسٌ فَلْيَخْدُمْكَ قَالَ فَخَدَمْتُهُ فِي الْحَضَرِ وَالسَّفَرِ فَوَاللَّهِ مَا قَالَ لِي لِشَىْءٍ صَنَعْتُهُ لِمَ صَنَعْتَ هَذَا هَكَذَا وَلاَ لِشَىْءٍ لَمْ أَصْنَعْهُ لِمَ لَمْ تَصْنَعْ هَذَا هَكَذَا