I picture the vast realm of the sciences as an immense landscape scattered with patches of dark and light. The goal towards which we must work is either to extend the boundaries of the patches of light, or to increase their number. One of these tasks falls to the creative genius; the other requires a sort of sagacity combined with perfectionism.
Being goal-oriented instead of self-oriented is crucial. I know so many people who want to be writers. But let me tell you, they really don't want to be writers. They want to have been writers. They wish they had a book in print. They don't want to go through the work of getting the damn book out. There is a huge difference.