Some men improve the world only by leaving it.

Oscar Wilde (1854-1900) Irish poet, wit, dramatist

(Spurious)

Not found in Wilde's writing; its earliest appearance is around AD 2000. Nor is a related quotation authentic to Wilde: "Some cause happiness wherever they go; other whenever they go," which first shows up in 1908, after Wilde's death.

Note that the orator Robert Ingersoll, discussing suppression of thought and mob mentality, wrote in his lecture "Plea for Individuality and Arraignment of the Church" (1873-12-21) (emphasis mine):

It is mortifying to feel that you belong to a mental mob and cry "crucify him," because others do; that you reap what the great and brave have sown, and that you can benefit the world only by leaving it.

That is the earliest reference I can find to that phrasing, but it is unclear if the phrase was borrowed from Ingersoll and put into the mouth of Wilde.