Excellence is underpinned by a deep commitment to get better.  Those driven to excellence are not wavered by the hard work nor the sacrifice that entails as they know these things are part of the process to get incrementally better.   Passion is a key initiator but is not enough to propel one to excellence, but rather it is the commitment displayed every day towards honing one's craft that separates those that achieve from those that simply want to experience the success.  There are no overnight successes, but only success built upon the successive nights committed to improvement.

Without commitment you cannot have depth in anything. Neil Strauss

Most people fail not because of a lack of desire but because of a lack of commitment. Vince Lombardi

Commitment is an act, not a word. Jean-Paul Sartre