Hakeemul Ummat Hazrat Moulana Shah Ashraf Ali Thanvi ra writes in Qasdus Sabil ila Mawla al-Jalil, a primer for those involved in tasawwuf and islah;

“Few of the sins are in particular extremely destructive for those traversing the sulook (spiritual path). They include:

1. Riya (ostentation/show off)

2. Takabbur (Arrogance)

3. Useless and sinful talking

4. Looking lustfully at ghair-mahram females and (young/adolescent) boys

5. Being angry inappropriately and/or excessively”

Tasheel Qasdus Sabil, page 25 & 26, by Hazrat Mawlana Shah Lutufe Rasool sahib ra (senior khalifa of Hazrat Hakeemul Ummat ra).