In The Name of Allaah, The Most Merciful, The Bestower of Mercy.
Mutarrif Bin Abdillaah Ash Shikh-kheer [rahimahullaah] said, “It is more beloved to me that I sleep all night [i.e. without performing the optional night prayer] and wake up in the morning whilst being regretful than stay up all night in prayer and then become self-amazed”. [Ref 1]
Imaam Adh-Dhahabi [rahimahullaah] commented on this statement and said, “The one who attributes piety to himself or is amazed with himself will not be successful”. [Ref 2]
[Ref 1: Az-Zuhd 448. By Imaam Ibnul Mubaarak (rahimahullaah)]