That last point is important - we learn new things because we find out that there are things that don't make sense to us, so we search out answers. If we are simply stamp collecting, then we will have no incentive to learn.
Ernest Rutherford famously said that "All science is either physics or stamp collecting". This demonstrates that had Rutherford tried his hand at biology, he would have epically failed. That's not to say that Rutherford wasn't intelligent, or capable. Indeed, he was probably more intelligent and capable than most people. Rather, he was uninterested. His experiences in the world had led him to the view that nothing other than physics was interesting. He would have seen no point in learning about biology, because it wouldn't have sated his curiosity.
I notice that the times I learn most are when I'm most interested and engaged, and that happens when what I'm learning about seems to answer, or at least hint at answering, questions that I had before. That feeling of discovery when you come across a potential solution to a problem you've had for a long time is a great one.
I suppose the fundamental problem of researchers, is that some problems are simply too big to have straightforward answers. The way to approach them is to use them as motivators, and search for leads. We become a little like detectives trying to solve a mystery. We use our prior experience and our imagination to attempt to find plausible clues, or leads. We will be interested in these leads because they seem like viable ways to answer our burning questions.
Ask any scientist or researcher what they are interested in, and they'll give you a list of topics. I suppose common ones include 'understanding intelligence/consciousness', 'understanding physics', 'curing cancer'. Maybe people are motivated for different reasons, and I'm sure that there are people out there who have an interest in these things because it might bring them riches, fame, or glory. But I feel like it's not really possible to make real progress in a field unless you're motivated by your own curiosity. There were questions we had as children, and they're probably questions that human beings have been trying to answer for thousands of years.
Maybe, ultimately, the question we are all asking is - "Who are we? What does this all mean?". It's a question every child probably asks themselves with or without knowing it, and its motivated humans to build civilisations, and led to the growth of philosophies, religions and other ideologies. All our questions are derivatives of those questions. We need to keep deriving questions until they are within our reach, and attack those, so that we can further penetrate the sea of ignorance in which our little bubbles of knowledge float. Maybe it's a higher-dimensional Non-Euclidean space of ignorance, in fact it almost certainly is. But let's keep penetrating till we hit other bubbles, or (gasp) finally break the surface and smell fresh air.
