Hofstadter's law states:
It always takes longer than you expect, even when you take into account Hofstadter's Law.
Introduced by Hofstadter in a time (1979) where chess-playing computers were continually beaten by top-level human players. He wrote:
In the early days of computer chess, people used to estimate that it would be ten years until a computer (or program) was world champion. But after ten years had passed, it seemed that the day a computer would become world champion was still more than ten years away. . . . This is just one more piece of evidence for the rather recursive Hofstadter's Law.