[garenp]

FWIW, I'd probably put myself in the same category the OP writes about.

I hit a wall in calculus 2 in University, because previously I had been able to rely on simply showing up and not putting in much effort to still do "pretty good". That was the first time I did poorly in any math/science course, and was a pretty big wake-up call. As a result, I ended up having to study more to fill in the gaps.

I was naive, came from a poor background with crappy public schools, and didn't think of math as particularly important to focus on until I saw how useful it was in physics. I don't think it's an all too uncommon story.