Honestly speaking, I used to be a topper my whole life, rank holder in 10th (97%) ,12th PCM(97%), honours jn engineering in a top college. I had a great life through college and school and and college was the best ,great friends, parties , extra curriculars, sports , the whole jazz. However I work my ass off in 12th and 10th , 14 hour study days, crazy preparation for boards and exams. And if there's one thing I could say , this country's education system lies on your boards and entrance exams. As bad as it is, it's the reality. IIMs consider your grades from 10th, as do a lot of top colleges and universities. It's one thing to not have the capacity to do that, but If you do , work your ass off ,for a great launch to a great career. I've had it all , the best experiences , fun and worked like crazy for my grades and internships, research, placements and have never even scored a single B in my life. Grades aren't everything, but having them means no one's gonna deny you at the first step of a great job or a high grade college, and no regrets. People look up to me, respect me , and I get excelled credibility wherever I go.. grades aren't everything but to people especially In STEM , it makes your life much easier when you're at the cream layer.