Sturgeon's Law: prov. "Ninety percent of everything is crap".

:Sturgeon's Law: prov. "Ninety percent of everything is crap".
Derived from a quote by science fiction author Theodore Sturgeon,
who once said, "Sure, 90% of science fiction is crud. That's
because 90% of everything is crud." Oddly, when Sturgeon's Law is
cited, the final word is almost invariably changed to `crap'.
Compare {Hanlon's Razor}, {Ninety-Ninety Rule}. Though this
maxim originated in SF fandom, most hackers recognize it and are
all too aware of its truth.
-- The AI Hackers Dictionary