While attending school, it's hard not to get caught up in stressing over grades. In high schools, grades help you to get into college. In college, grades help you to get into grad school, get internships, or get jobs. Financial aid and scholarships even depend on grades. GPA is so emphasized that it can lead to stress and perfectionism; some people are always striving to get the best GPA possible.
In high school, I was the person who would get upset if I didn't get an A. I would be extremely disappointed in myself and think that I should've done better. Over time, however, I've ditched this mentality and learned it's not healthy.
Too much stress is a bad thing, and stressing over grades constantly doesn't help. Yes, you should always try your best to get good grades, but you shouldn't let the obsession with getting A's consume you to the point where you are left worn out.
Sometimes, you're in a tough class and no matter how hard you work, you can't seem to get that grade you want. Sometimes, the class just doesn't align with your strengths. My freshman year of college, I took calc, which was both a tough class and one that didn't align with my strengths. I didn't end up getting the best grade, but I knew that I put in a lot of work and effort. The class just didn't click with me. That happens sometimes, and as long as you know that you're trying your best, it's okay.
Sometimes, it's less about the grade and more about if you feel you learned something. You might not be the best test taker or paper writer but still feel as though you took a lot away from the class. You might be able to apply and memorize everything you've learned in a class even if you didn't ace it.
Even though I have ditched the "I need to get all A's or else I'm a failure" mentality, I still strive to do my best and get good grades. Grades are definitely important, but they aren't the only thing that matters. Getting some B's or even the occasional C will not ruin your life or your chances of getting a job/into college/into grad school. Always try your best, but don't be too disappointed if your best means you fall short of the A mark.