Science is what we understand well enough to explain to a computer; art is everything else.
The best programs are written so that computing machines can perform them quickly and so that human beings can understand them clearly. A programmer is ideally an essayist who works with traditional aesthetic and literary forms as well as mathematical concepts, to communicate the way that an algorithm works and to convince a reader that the results will be correct.
An algorithm must be seen to be believed.
Premature optimization is the root of all evil.
Beware of bugs in the above code; I have only proved it correct, not tried it.
Nearly every example of faulty reasoning that has been published is accompanied by the phrase "of course" or its equivalent.