[Suppafly]

Not programming, but all the math classes that were required as part of the major. Most of the programming classes were challenging in that type 2 or type 3 fun way, where they are challenging but you lowkey enjoyed the challenge. That said, I went to a bit of 'java school' so the programming classes weren't as tough as some other schools.

Automata is a good one to give you some understanding of how things work 'underneath'. The different algorithm ones are good because by implementing algorithms from scratch you learn how they actually work and that helps inform when you'd choose specific ones. I find that a decent background in algorithms is what really separates the self taught folks from the college educated ones.

Database programming was kinda tough, at least the theory side of it, because relational algebra and relational calculus are complicated and the whole normalizing databases during the design stage of things.