How can you own [...] numbers? Numbers belong to the world. - Donald Knuth

If you find that you're spending almost all your time on theory, start turning some attention to practical things; it will improve your theories. If you find that you're spending almost all your time on practice, start turning some attention to theoretical things; it will improve your practice.

People who are more than casually interested in computers should have at least some idea of what the underlying hardware is like. Otherwise the programs they write will be pretty weird.

Beware of bugs in the above code; I have only proved it correct, not tried it.