Sturgeon's law: "Ninety percent of everything is crud." Derived from a quote by
science fiction author Theodore Sturgeon, who once said, "Sure, ninety percent of science fiction is crud. That's because ninety percent of everything is crud." Oddly, when Sturgeon's law is cited, the final word is almost invariably changed to "crap".
Sturgeon's law might be regarded as an instance of the Pareto principle.
See also: -- Murphy's law -- Finagle's law -- Hanlon's razor -- Law (principle)