On the authority of al-Awzaa'ee - may Allah have mercy upon him:
"When Allah wants to prohibit His servant from the blessing of knowledge, He renders 'al-'Aghaleet' over his tongue."
[Jaami' Bayaan al-'Ilm wa Fadlihi: 1087 - by Ibn 'Abdul Barr.]
What is meant by 'al-Aghaleet', are the difficult and strange/controversial issues that one tasks himself to take on with difficulty, and asking ill intended questions that raise doubts and therefore lead to excessive argumentation and increase disputes. Whoever's objectives are limited to following these issues and does not have the aim of understanding [the sayings] of Allah and His Messenger and their meanings, and learning the boundaries of what was legislated that would in turn lead to friutful actions, then this person has wasted his time and has been prohibited the blessing of knowledge.
Translators note: i.e. The blessing of knowledge is to learn what Allah has legislated in a manner that would lead one to practice what He has ordered and abstain from what He has prohibited. If you find yourself constantly involved in affairs that do not lead to fruitful actions, then you are being prohibited from the blessing of knowledge and should reconsider your approach…