This is a big one (for me at least). A downside of being more knowledgeable on a lot of topics than the people around you is that you can develop a certain hubris that's not good for learning. Learning something new you absolutely suck at is a great way to regain some humility. And having some humility is absolutely needed when you want to be teachable.
"Personally, I am always ready to learn, although I do not always like being taught." - Churchill