" Learning is often paradoxical. The very thing we need in order to learn impedes our ability to learn. We need to focus intently to be able to solve problems—yet that focus can also block us from accessing the fresh approach we may need. Success is important, but critically, so is failure. Persistence is key—but misplaced persistence causes needless frustration. "

― Barbara Oakley , A Mind for Numbers: How to Excel at Math and Science (Even If You Flunked Algebra)