If you have a fixed mindset, every situation you encounter is a referendum on whether you have the smarts or ability that you think (or hope) you have. “Fixed” kids do fine when the puzzles are easy. But when they start to struggle, they hear the puzzle whispering to them: Not enough puzzle smarts. You are not up to this task. They become discouraged, impatient, embarrassed. Better to quit than to continue to face what they lack.