Engineering and science are slow fields. Yes, you read about breakthroughs, revolutions, and the like, but those headlines are the fruit of years of labor. I acknowledge that all fields require planning, thought, and care, but the businessman can just go out and make a deal (perhaps a bad one) in a fairly short amount of time. You can't just go out and build a bridge (however poor) in an afternoon, or even a week. Enough anecdotes.
If you want to pursue an education, especially in the science/engineering fields, you must commit yourself to it for substantial periods of time. This is not easy. It is done at the expense of fun, friends, and even perhaps family. As a PhD student, I do not get to spend nearly as much time with my wife as I did when I was a practicing engineer. It is a very rare weekend when I can hang out with friends. A good education makes demands on you.
All this to say, if you are serious about learning, you will learn. If you are unwilling to give up time, energy, and other activities, you will not gain insight into your field. Your institution may pass you, you may well get a job, but where will you be when you must puzzle through a thorny problem all alone? What training can you lean on if you forgot it after the test?
If you choose to study, study what you love, and study hard. It will pay you back in its own time, and you may even discover that learning is its own reward (and even if you don't discover that, you will still be able to do more jobs better, and you'll get paid more).