Why do I even try?

I handed in a travesty of a paper for one of my classes recently. I had absolutely no interest in the topic, and it barely applied to the theme I’m supposed to be sticking to this semester. I knew it was bad, but I had to hand in something, so I gave it as little effort as I could, and handed it in. A day late. And a page short. In a larger font and typeface. I got an 81, meaning it could have been higher, if it hadn’t been docked for being late. I actually tried on the first paper for this class, too. I don’t get it. She isn’t an easy grader, and people got lower grades than I. I don’t even know why I bother trying anymore.