I think of this more along the lines of the way Kirk Karwoski summed it up. He believed that all he had to do was not screw up for 20 seconds and he would make the lift.
That is being positive, but it also acknowledges that failure is possible. However, then blame for the failure was because of form or fate, not his mental or physical strength.
To take the sprinter example, 7 out of 8 of those guys will likely point out flaws in their race rather than their belief that "failure is not an option" is invalid.
For me personally, it helps me to have noting but positive thoughts and visions of making a successful lift before every heavy lift. If I doubt before lifting it, I miss it more often than make it.
I am Anton Zdravko Martin!
Best meet lifts: Sq 150 Kg (330 lb), Bench 120 Kg (264), DL 160 (352) @89 Kg (197)
Best gym lifts: Sq 375, Bench 280 (pause), DL 385 @205 or less
Goals beyond my wildest dreams, 600 Kg raw total, 200/160/240
Hack away at anything which isn't essential. Do what you love, and do it often. Fazc.
Everything competes for recovery so more assistance is not always the best idea. miked96