The pursuit of excellence is not a goal
Excellence and mastery are not commitments or goals, but a constant pursuit. They are not a balance that you seek and find, they are a fragile state that you must maintain through constant behaviour adjustments; by reinventing solutions to work with changing parameters.
Can this be done better? Am I really the best person for the job? What is the problem we’re trying to solve? Maybe that change your manager wants you to try isn't such a bad idea? Question everything, including yourself and that's the only effort you need to create the momentum needed to pursue excellence.