I have a really hard time quantifying how useful any of my college courses were. There are various pieces that turn up in things I work with. Parsing with data, some specific algorithms and data structures, design and structure, b-trees, security and more.

But many shaped how I think k about all of those,memory layouts, complexity analysis, statistics, discrete math, crypotgraphy.

Maybe I am deluding myself into valuing something I spend a lot of time on, maybe picking out those bits I use day-to-day and just learning them would make me a worse e gineer.

Overall, I find conclusions of the Form "I only directly use X" often unconvincing, because some people I had this discussion with could not recall they actually did learned something in college, which they claimed was never covered. (again, my memory might be the faulty one...)