WIST

The lives of happy people are dense with their own doings — crowded, active, thick. [...] But the sorrowing are nomads, on a plain with few landmarks and no boundaries; sorrow’s horizons are vague and its demands are few.

Larry McMurtry (b. 1936) American novelist, essayist, bookseller, screenwriter
Some Can Whistle, pt. 4, ch. 9 (1989)

The scientific man does not aim at an immediate result. He does not expect that his advanced ideas will be readily taken up. His work is like that of the planter — for the future. His duty is to lay the foundation for those who are to come, and point the way.

Nikola Tesla (1856-1943) Serbian-American inventor, physicist, engineer, futurist
“The Problem of Increasing Human Energy”, The Century (Jun 1900)

No public man can be just a little crooked.

Herbert Clark Hoover (1874-1964) President of the US (1928-32)
Comment (1951)
In Louis Lochner, "Herbert Hoover in His Own Words," New York Times Magazine (9 Aug 1964)

Politics is not an exact science.

[Die Politik ist keine exakte Wissenschaft.]

Otto von Bismark (1815-1898) Prussian statesman
Speech, Prussian upper house (18 Dec 1863)
In 1884, when speaking in the Reichstag, Bismark offered this variant: "Politics is not a science, as the professors are apt to suppose. It is an art." ["Die Politik ist keine Wissenschaft, wie viele der Herren Proffessoren sich einbilden, sondern eine Kunst."]

We all too often have socialism for the rich and rugged free market capitalism for the poor.

Rev. Martin Luther King, Jr. (1929-1968) American clergyman and reformer
(Attributed)
This phrase is frequently attributed to King, often pointing to some 1964 speech, though the exact phrasing can't be found in his works. He did use variations of the phrase on a number of occasions (e.g., "The Other America", speech at Grosse Pointe High School (14 Mar 1968), but it's also a construction that's been used by others before and after King.