Hakim al-Umma Shaykh Ashraf Ali Thanawi (Allah have mercy on him) wrote,
‘From the impediments of the path two are specially so prevalent that it is rare if any of the travelers has escaped not being involved in them. Even the learned scholars are involved in them.
One of them is striving to acquire some non volitional (ghair ikhtiyari) things. That are, things like engrossment, enthusiasm, intense & deep concentration, ecstasy, serenity, blocking of disturbing thoughts, burning desire, overwhelming attraction, emotional love, etc. It is assumed that these are the results of remembrance (dhikr), concentration exercises (shugal) and spiritual struggle (mujahidah). Moreover they consider themselves to be at loss when these things are not achieved.
The other impediment is striving to remove some non volitional (ghair ikhtiyari) thing. For example, spiritual constriction (qabd), overwhelming thoughts, not developing interest, love of an individual, innate love of wealth, sexual desires, excessive natural anger, not having softness of heart, not being able to cry, overwhelming worldly sorrow or fear, etc. It is assumed that theses things are detrimental for the path and are an impediment in achievement of the goal.’
Al-Usool al-wusool, page 20