Hard to answer without understanding your end goals.....
This said, I can really empathize with what you are saying. In my case, I think sometimes i just want to feel more "in control"---ie I want to feel secure in knowing how the system works---to allow me to solve my own issues, to teach others, to quit my day job---who knows??
It is a big leap from shell scripting to kernel hacking....
In between, you might need to learn some programming skills and a whole lot about OS theory and practice.
In my case, I have visions of writing some of the applications that I see as BIG holes in the current Linux repetoire. At age 64, this may be a bit of a reach. Meanwhile, I just try to keep learning.
