> I don't think I could have gotten there with toy/educational examples online/in books.
For programming, the available documentation is not just ludo-educational, it's also the official references, like the RFCs and specifications. There is literally no better source of knowledge for computer science. I haven't delved into technical specs very often in my life, but I have at times and I bet most good programmers do it often.
It wasn't until I used Linux professionally that I started to really respect (and enjoy) using the environment. And even then it wasn't until I saw another human using it efficiently. It's one thing to read about how useful it is, it's another thing to struggle with a problem and have someone show you how you could solve your exact problem.
Once I had that connection with another human/mentor, seeing my specific problem solved, that's what hooked me. I don't think I could have gotten there with toy/educational examples online/in books.