Among Those Affairs That Led a People Away From the Sunnah and the Jamaa’ah!
Imaam Ibn Battah (rahimahullaah) stated:
Know, O my brothers! I have pondered over the reason that expelled a people from the Sunnah and the Jamaa’ah; compelled them to bidah and ignominy; opened up a door of trial upon their hearts and veiled their discernments from the light of truth; so I found that (coming) from two angles:  (Unnecessary) research and argumentation; asking too much concerning that which is of no benefit—(affairs that are) neither harmful to the ignorant intellect nor beneficial to the understanding of the believer.  The other (reason is): Sitting with a (person) whose Fitnah one is not safe from and (is a means of) corrupting the heart of the one who accompanies him. [Slightly paraphrased. Al-Ibaanah Al-Kubraa 1/390]