In such a volatile environment, a single setback -- a grant that falls through or a snowstorm on a show date -- can upset the balance.
At his press conference, Mr. Bush gave a progress report on the war to date -- and found solid advances on every single front, without a single setback, not even a minor one, of any kind.
Although she recently accepted a Disney gig set to make her the first black woman to direct a $100m movie, DuVernay understandably suspects that a single setback could see her career flounder in a way that a white, male counterpart's might not.
It is the end of a fine sequence that has put Liverpool back on the brink of the top four, so it would be a surprise if confidence was dented too much by a single setback.
Egypt won't give up on its diplomatic efforts after a single setback but the resumption of hostilities means the question of whether Israel will eventually order ground operations is back on the agenda.
"America has never declared defeat after a single setback –- and we shouldn't start now.... It's time to do what we've always done in the face of a tough competitor: roll up our sleeves and recapture the lead".
