Piss And Vinegar Meaning

(US, idiomatic) Exuberance or enthusiasm, especially to an excessive degree; bravado; youthful energy. [from mid-20th c.]

Example: 1940, John Steinbeck, The Grapes of Wrath, Viking, p. 248:
  "I know what's a matter. Young fella, all full a piss an' vinegar. Wanta be a hell of a guy all the time."
2008 Oct. 2, David Fricke, "Q&A: Metallica's James Hetfield," Rolling Stone (retrieved 21 Feb. 2009):
  Everyone wants that: the vigor, fire, piss and vinegar. You really believe that you're taking on the world.