It is amazing the amount of stress that goes away when you just stop giving a damn. I just took my final exam for Computer Organization and Architecture (my hardest class), and I know I failed. I know this because I left three questions unanswered--together, they equaled twenty points. Also, I just infodumped for most of the questions. I think there was only one question that I was absolutely certain of on that exam.
Not caring is great. Perhaps not so much for my grade, but for my stress level? Certainly.