I graduated from a very highly rated high school in California in 1966, having taken Algebra 1 and 2, Geometry, and Trig. I felt pretty good about my math skills, and always got As.

I went off to engineering school in New York, where every freshman from New York (and that was about 60%) had had a year of calculus.

THEN I found out that there wasn't just ONE calculus class. Besides the one named "Calculus I," there were three others, namely Mechanics, Physics I, and Chemistry I.

It was a miserable year. To make matters worse, I had never had to really work at something that didn't come easily. I had never heard of the concept of tutoring, and was too socially inept to find a study group.

The next year I had Thermodynamics. I was an EE student, but at the time ALL engineering students took the same core courses for the first 5 semesters. More calculus, of course, and I remember wondering when an electrical engineer was going to use steam tables, or anything else in that course. Well, I never did.