Don’t Repeat Yourself’, or DRY, is taught by many make-yourself-a-better-programmer books — a genre of publishing which always reminds me of relationship self-help books. DRY says that the same concept shouldn’t be given more than one expression in the code. But taken to extremes, DRY means that any comment saying what a program is trying to do is redundant, because a program is by definition already a statement of what it does. Don’t repeat yourself, in other words, can be taken to mean: never explain yourself.