A willingness to be stuck

“Many people have tried that problem,” Iwaniec said. “He’s a private guy. Nothing is rushed. If it takes him another ten years, that’s fine with him. Unless you tackle a problem that’s already solved, which is boring, or one whose solution is clear from the beginning, mostly you are stuck. But Zhang is willing to be stuck much longer.”

From The Pursuit of Beauty (via Knowing and Doing)