Perfect grades are a trap because you bust your ass for the demoralizing position of having nowhere to go but down. I found it more rewarding to leave a little room for improvement.
Besides, calibrating people's expectations of you a little lower not only takes the pressure off--it leaves you in a better position to under-promise and over-deliver.
Life's a treadmill my dude, and you can't outrun a treadmill. Gird your loins for the long haul, pace yourself, take breaks, and try to remember that the most common reward for struggling through something you don't enjoy is being tasked with an even more tedious version of that same thing. Other people's expectations are bait that lures you into the trap of devoting yourself to shit you don't find meaningful. Don't take the bait.