We grow up thinking of our achievements as being either successful or a failure. Believe me, I've spent my life unwilling to quit things. Those who are stubborn will often go far -- too far -- to ensure it's not a failure. But that is not always smart. In fact, there is a time to quit.
The definition of success is truly in "the eye of the beholder." What for one person constitutes having achieved everything they've ever wanted might be seem like a gross underachievement to someone else.
This is the paradox of life: you usually have to fail utterly and completely in order to succeed. Success, it turns out, is an inside job. You can pretend it's not, but in the end you will fall flat on your face.