Everyone can think of learning moments when things broke down. One reason for this is that experts often make poor teachers. Once you've mastered a skill, it becomes difficult to remember what it felt like to not know the skill. Once you know how to ride a bike, you might say to a newbie, just push off. Start pedaling. It takes an enormous act of effort, of empathy to go back and remember how it felt when something seemed confusing or impossible. This is sometimes called the curse of expertise. Experts forget how difficult it can be to learn something because they've already mastered it.