nisbat is another name for "Ta,luq ma,Allah", it is obviously a very pleasant feeling,which attracts towards more ibda,and therefore more strength in nisbat. In other words we can say that constant Ibadat & zikr produce some effects on Nafs & rooh which leads to more thirst of association with Allah swt,resulting in more efforts and so on. salbe nisbat ,therefore will mean somehow,clouding the pleasure associated with nisbat,but not nisbat itself,as no one can break the nisbat of haq & khalq.if the effects of salbe nisbat remains limited to this and salik continues to perform his ibadat, no harm done,but in most cases in the absence of Inshirah associated with nisbat, ibadaat slows down and a negative cycle sets in place ( Nauoozo billahe min Zalik), But why would one do it ? Generally for the betterment ! a young person came in presence of Hazrath Mujaddad sarhindi ra whose zikre qalbi was so loudly heard when he would be asleep that people would gather around him.Hazrat Mujaddad ra noted that this phenomena is producing vanity in him and is taking him further away from Allah swt,so he "salb" his Zikre Qalbi,that person first became angry,then started crying and after a few days became depressed and subdued,now Hazrat Mujaddad asked for him and granted him much more than just loud Zikre Qalbi by Twajjo.The purpose was never tp punish him but to treat his vanity. "Imdad ul mushtaq" narrates a story that in Haram sharif a chishty would always compare salasil with each other proving Chishtiya to be the best and all others just fake.A Naqshbandi Shaikh in Haram would always tell him in a very cool way that your love for Chishtiya is appreciated but down grading other Akabir is not, but as the Chishti would not listen,one day the Naqshbandi shaikh salb his nisbat.This was for punishment. ( The Rawi of this incident is Hazrat Haji Imdad ullah ra) so the occassions can be different, but it is never without a valid reason,as all shyookh are fully aware of their responsibility to Allah swt. Having said that, i agree with shaikh fusoos,that instead of discussing this rather rare phenomena, we should be discussing how to create nisbat. Tou barae wasl kardan amadi Ne barae fasl kardan amadi You are to connect people to Allah,rather than to break them away from Allah.