I have a degree in Computing Science. I’ve had a formal higher education. We covered a lot of ground.
I’ve learned about information retrieval, database normalisation, memory management schemes and paging, functional programming, distributed systems and synchronisation problems, matrix mathematics and image convolution kernels, Bézier curve construction, Fourier transforms, maps and trees and tries and doubly-linked lists, sorting algorithms, O-notation and time complexity, SQL, OO, NP-completeness and hardness and polynomial-time approximations, cryptography, multitasking models, user experience design, affordances, safety-critical systems, at least a couple of dozen programming and scripting languages, finite state automata, grammars and Backus–Naur, graph theory and colourings, compiler design, language design, hardware design, and… a hundred other things.
I’m a writer now, but all of that stuff still interests me, even if I have little reason to use it. If you were to ask about the single most useful thing I’ve ever learned within the sphere of technology – the thing I’ve most appreciated, found most satisfying, and had most use from, in diverse situations, all the time – I could answer easily.
I’d say: regular expressions. If you’d like to learn something new today, you could start here.