Ashutosh Jogalekar in The Curious Wavefunction:
What makes a successful scientist? The question is hard to answer, not because there is no general consensus but because the precise contribution of specific factors in individual cases cannot always be teased out. Intelligence is certainly an important feature but it can manifest itself in myriad ways. Apart from this, having a good nose for important problems is key. Perhaps most important is the ability to persevere in the face of constant frustration and discouragement. And then there is luck, that haphazard driving force whose blessings are unpredictable but can be discerned by Alexander Fleming's famous “prepared minds”.
But aside from these determinants, one factor stands out which may not always be obvious because of it's negative connotation; and that is the good sense to realize one's weaknesses and the willingness to give up and marshal one's resources into a more productive endeavor. Admitting one's weaknesses is understandably an unpleasant task; nobody wants to admit what they are not good at, especially if they have worked at it for years. That kind of attitude does not get you job offers or impress interviewers. Yet being able to admit what qualities you lack can make your life take a radically successful direction. And lest we think that only mere mortals have to go through this painful process of periodic self-evaluation and subsequent betterment, we can be rest assured. It was none other than Linus Pauling who went through this soul-searching. And we are all the wiser for his decision.