I've often heard - and said - that grades don't matter. What's interesting about this is that two people can both say 'Grades don't matter' and mean completely different things.
What different things could they mean? This comes down to a distinction that I've only recently grasped in terms of something I can explain concretely and it has to do with living life on 'Hard mode' vs 'Easy mode.' You could also describe it as short term vs long term thinking.
The first interpretation - Grades don't matter. All that matters is passing and getting the piece of paper. Sometimes the tests are badly written or the assignment structure is lopsided, so you should forget about trying to learn properly and just cram the night before. As long as you scrape over the line, it will cease to matter once you have a job.
The second interpretation - Grades don't matter. All that matters is understanding. Sometimes the tests are badly written or the assignment structure is lopsided, so it can be hard to demonstrate your understanding and get a good grade. But grades don't matter as long as you understand and remember what you've learnt.
This is a pretty fundamental difference in the way you view the world. Do you want to put in the minimum effort to get to your goals, focusing on the short term, on passing the next test? This is easy mode. Or do you strive to gain understanding and mastery. Working on the core concepts and not rote procedures, something less easily measured with tests and that might not pay off for years. This is hard mode.
The best way to understand something is with examples. The inspiration for this post was the following two, take a read if you have the time and interest:
The main idea here is to self examine how you do things - are you taking things the hard way or the easy way? Why is this distinction important? Neither the hard way or the easy way is always the correct choice, but it's a useful lens to look at your activities through. If you don't at least see the difference then your decisions are less informed.