وَعِنْدَ ضِيقِ وَقْتِ الْمَكْتُوبَةِ، وَمُدَافَعَةِ الْأَخْبَثَيْنِ، وَحُضُورِ طَعَامٍ تَتُوقُهُ نَفْسُهُ، وَمَا يَشْغَلُ الْبَالَ وَيُخِلُّ بِالْخُشُوعِ
Starting Nafl is disliked when the Fard time is dangerously narrow, while urgently resisting urination/defecation, when desired food is present, or when another avoidable distraction seriously harms Khushu'.