<p>Two random thoughts:</p>
<p>(1)
I recommend putting in the effort even if writing isn’t an important part of your major. For one thing, it’s just important to know how to get your thoughts across clearly, no matter what you want to do. For another, though, I knew some non-humanities majors who struggled with writing, and all of their grades suffered from the huge amounts of time/energy they had to dedicate to occasional writing assignments. </p>
<p>(2) There’s an element of luck involved, particularly at the 3.9 level. Of course, that’s not all it is–hard work, intelligence, savviness, etc. are the main players–but it’s certainly a part. In my experience, there was more subjective grading in college than in HS. Every B+ I received in college could be explained more by bad luck than by lack of effort or objectively poor performance. Of course, I also received a few A’s and A-'s that didn’t at all reflect my actual understanding (or lack, thereof…) of the material! It goes both ways.</p>