Very popular nowadays is the idea of unlearning. I would say how it's very important is because what you have learned can have enormous impact to your experiences, let alone the process of thought.
Let start with this. As the crimes rise nowadays, when almost everybody says "How monstrously can he do that?", it practically means "How mercifully could I have done that?". This can show how narrow their mind is. What should have happen may be thinking like "What condition in this universe can he do that?" than "What heavenly condition in my world could he do that? (Like you come from heaven and he is from hell!)". It's (also) a pity for me when I see people keep alternatingly pitying others OR hating others all the time. Ironically, you'd be better keep pitying AND hating others ALL the time, because those are always present whether or not by your witness. And both 'others' are the same 'others', the difference is trace. Can we really manipulate those traces? Can you even manipulate your thoughts to be hardly deviated toward my reasonable logic? Should we better concentrate more on the big picture?. Those are just results, not causes of the chain of problems. Broadening your mind is the point.
Extendingly into some logical way of disagreeing knowledges, it is much better for you to understand some opposite way of thinking than keep digging through what is your strength (more accurately a strong bias). Examples are progressive or conservative, capitalism or socialism, globalism or nationalism, heavenly way or monstrous way (just example!). Even if your goal is to be more persuasive about your standpoint, it should help. But the most important thing may be to prevent or prepare from diverging or reversing world, which is practically happening.
Immediate effect of these is more balanced peaceful mind. Further effect may be more chance of success, inclusively, hopefully.