Highest Office Held: President of the United States
Yes, there is such a thing as too much integrity. When Truman left office, he insisted that he couldn't be on any corporate payroll, and that he wouldn't do endorsements of any kind. He felt that such moves diminished the integrity of the presidency. These high-minded ideals are fine as ideals, but in practice, they didn't work out. Because Truman became a man without money.
Directly after leaving office, he was living on a little over $100 a month. As far as Congress was concerned, this was not a good look. The Former Presidents Act was passed in 1953, granting all ex-POTUSes a $25,000 yearly pension. The wealthy Herbert Hoover took the pension so as not to embarrass Harry.