[nitrogen]

I definitely agree. It is the simplicity of the POSIX userspace APIs and the Linux kernel internals that make me enjoy Linux so much.

I still think there is some art to writing simple, efficient code, though. Most system-level code looks quite simple when it's done, but it may have taken several iterations to get it fast, clean, and small enough (particularly on embedded devices -- I once had to find 200 spare bytes to fit a bug fix in a 256KB firmware by hand optimizing various ancient parts of the code base).