[leif]

Since you seem to have at least something of a handle on the LISPs of the world, go master C. Embed in your brain everything about pointers (and multiple indirect pointers), structures, offsets, row-major ordered higher-dimensional arrays, fancy macros (try containerof), why inlining and loop unrolling makes things faster, static variables and functions (and the difference between them), what happens when you compile, assemble, and link, and work your way around libc for a while and use some syscalls.

After this, every time you do something in another language, you'll be able to figure out exactly what is happening. Debugging will become second-nature, and you'll appreciate other languages more. :)

Obligatory BSD warning: http://xkcd.com/349/