The person who can stay with a difficult thought develops uncommon leverage.

Most people leave a difficult thought quickly, because holding it is uncomfortable and there is always something easier available. Someone who can stay with it, past the discomfort and past the first plausible answer, reaches places others do not. That capacity is unusual, and it compounds into real advantage.

Pick a hard question and stay with it for twenty minutes past the point you want to stop. Do not resolve it prematurely. The ability to remain in unresolved difficulty is trainable and worth training.