A novice programmer was once assigned to code a simple financial package.

A novice programmer was once assigned to code a simple financial
package.
The novice worked furiously for many days, but when his master
reviewed his program, he discovered that it contained a screen editor, a set
of generalized graphics routines, and artificial intelligence interface,
but not the slightest mention of anything financial.
When the master asked about this, the novice became indignant.
"Don't be so impatient," he said, "I'll put the financial stuff in eventually."
-- Geoffrey James, "The Tao of Programming"