Don't get me wrong. I like a lot of things that are in Linux. The ability to have control over everything, for example, is cool and nice. I also have a burning desire for knowing how everything is put together.
However, going back to your analogy, while I might not currently know how to change an oil filter, if I were a mechanic, I could certainly find out how to do it. The only problem is that I would hate doing it. Usually. The more time I have to spend figuring out how to get something working, the more annoyed I become. It's my nature.
I also realize that this might not be a good programmer attitude, and fortunately for me, I know I can get away with it because I am not, nor do I intend to become, a professional programmer out in the industry. It's a hobby, and it will probably not become something more than that. At least not when working for others, and for the time being at the very least.