Will and effort

"If there is no dark and dogged will, there will be no shining accomplishment; if there is no dull and determined effort, there will be no brilliant achievement."

~ Chinese saying (quoted in How to get on to the system;: A guide to the A.I. Lab timesharing system for new users (M.I.T. Artificial Intelligence Laboratory. Artificial intelligence memo)).

Also read: Lang Lang and deliberate practice