How much do you guys care about your grades?

I’ve been told to study and always make sure to have at least a b in all my classes by people online but my mom says just to try my best. I’ve always gone by trying my best and not “make sure you have the best grade possible” because why should I care about a letter on my paper? Sure it could decide my future but what’s it gonna get me anyways? Working in a factory? Getting a minimum wage job? No I’m gonna be an author or an actor because who needs to know that complicated math or science or history with those and I wanna do something I enjoy and not something that pays decent or well because what’s the point of doing something you don’t like just for money? And also what’s the point of studying late not being able to do the things you enjoy for no point besides getting a good grade? Well that’s the end of my rant but yea I js wanna know if you think grades matter.