I cannot stand it when a professor says that the best way to get an A is to learn. It shows a fundamental ignorance about their own system of instruction.
If there is anything I've learned about universities, it is that learning is at best orthogonal to getting an A. More often you have to actively sabotage your actual learning in order to get an A.
When you get excited about a subject enough to explore it on your own, you will almost inevitably end up either spending too much time on one part of the curriculum or neglecting the rote memorization and tedious busy work that is necessary to get an A. Classes are just small factories, treating and evaluating every student the same way. It is and ever was a game of points and percentages. If you want "learning" out of this, you need to balance it with playing the game.
Professors have either never known this or have completely forgotten it. They constantly whine about how students seemingly strive to get the least out of their education as possible by taking as many shortcuts as they can. What they fail to realize is that all of their classes are set up as silly little point games, and each student has about 5 or 6 of them. Then they give out so many busy work assignments and so much reading per class that it is impossible to accomplish it all. The students are essentially learning how to prioritize and cut out all of the unnecessary fat in order to maximize their points. They're kept so busy that they don't even know that they're not really maximizing for learning. Learning is not what the professors tell them to do. Learning is not what the professors hold over their heads. They live by points, and die by points. It takes a special student to pull his/her head out of this firehose of tasks and decide to pursue their own education.
So Bob the student comes into class and he hasn't done the reading. Why? Because he has spent 102% of his time on the various homeworks and deliverables for this and other classes -- the stuff that actually has an effect on the bottom line: his grade. He'd sure like to do the reading, but he knows that he can get the assignments done just as well without it, and so it goes to the bottom of the priority list. He will never get around to doing the reading, because the list of grade-impacting busy-work deliverables will never cease.
The professors then complain about the students like Bob, who don't seem to want to actively explore their subject. They complain about the work of their own hands, the inevitable result of their own system. The professor actively molds students to be this way, and then they complain about it.
That is what I wish I'd known as a freshman.