For me, it was the requirement to do so many calculus problems. I could have sown I was going to be doing comically difficult math problems out of school, and I don’t think I’ve done a single calculus problem in nearly 15 years. Don’t get me wrong, I’ve done tons of pretty intense math (mostly fluid mechanics), but I just expected calculus to have such a bigger footprint in the engineering world.
I fondly remember a discussion with a student on r/vhdl. She had issues with her project, nicely asked for help (in contrast to others who barged in and basically demanded “make my homework”). So she got help to refine her project.
We discussed her work afterwards, and she asked what I think of it. I told her that I consider it a nice little project for a lazy Friday afternoon. She was totally shocked by that assessment. It was her bachelor thesis…
That was not me being mean. It was a honest assessment. Enjoy studying while it lasts.