Most researchers do not do their best work during their PhD, but after it. The PhD is simply the training you need for a research career. It's an easy path to d

Most researchers do not do their best work during their PhD, but after it. The PhD is simply the training you need for a research career. It's an easy path to disillusionment when PhD students don't realize this (often because advisors don't do a good job helping the students set reasonable expectations and goals). It's good to be ambitious in problem selection. But a huge part of the training is to learn how to break down hard problems into reasonable increments that you can attempt to solve, one at a time.