What are the biggest obstacles to attaining true knowledge, and how do they work?

According to the teachings in Chapter 50, the primary obstacles to knowledge are Desire (Kama) and Anger. Knowledge is hidden by ignorance, which is fueled by lust and anger, much like a clean mirror is covered by dust or the light of a fire is obscured by smoke. The text states that Desire is the cause of all disasters and the driving force behind all actions. When the fulfillment of a desire is obstructed, that same desire transforms into Anger. Chapter 50 explains that this tendency is a major hinderer of knowledge and liberation, as Desire and Anger dwell right next to the Brahman-form, constantly posing a threat to one's spiritual progress.