How the university lectures go:

"Here's a design theory, here's another, and another, and another. Be sure to master these techniques for the exam, because they'll be with you for the rest of your career."

How the industry design practice goes talking with the senior electronics design engineer:

"Whilst I was high/drunk/sleep deprived from insomnia/all three at the same time, I drew up this circuit schematic last night and finished at 6am then got into the office for 8.

The calculations for these resistor and capacitance values? Idk, they just feel like the right values based on what I read in the data sheet. If they're wrong who cares, we'll stack SMDs on top or just respin the boards because PCBs and passives are cheap and we'll (read: you'll) desolder and reuse the more expensive ICs.

My design justifications notes? Haha that's your job, silly junior engineer. Oh by the way, I'll make value changes to 80% of these components fixing my mistakes, also known as 'tuning the sensor circuits', before I update the schematic. Even after it goes into production I'll just pinch boards off the line and change some things in the BoM without writing an ECO because I don't have time for that.

Yes I do still prefer to use leaded solder without an extractor fan, why do you ask?"

That engineer will either be the most liked person in the company or the most hated person in the company, yet either way are clearly un-fireable.