Page "Worse is better" Paragraph 7

; Completeness: The design must cover as many important situations as is practical.

All reasonably expected cases should be covered.

Completeness can be sacrificed in favor of any other quality.

In fact, completeness must be sacrificed whenever implementation simplicity is jeopardized.

Consistency can be sacrificed to achieve completeness if simplicity is retained ; especially worthless is consistency of interface.