Too Much Knowledge Can Also Create A Big Ego

If you are too knowledgeable, that can also give you a big ego. Gaining knowledge, skill can give you sense of achievement. You may condescend to people without realizing. 

Your Knoledge Is Partial

No matter how much you know, you only know part of the whole. You only solved few puzzles. The vast universe of knowledge is ever expanding. The more you find out, the more there is to explore. It is designed that way. So, you always know part of it.