This is a great thread, great ideas everyone, especially Giovanni with the phrase.
While we're on the subject of mantras, I just wanted to add a good one from Frank Herbert's Dune series.
This is the "Litany Against Fear," a poem characters recite to themselves when they're scared.
The long version is:
"I must not fear. Fear is the mind-killer.
Fear is the little-death that brings total obliteration.
I will face my fear. I will permit it to pass over me and through me.
And when it has gone past I will turn the inner eye to see its path.
Where the fear has gone there will be nothing. Only I will remain."
The short version (familiar to those who've seen the "Children Of Dune" miniseries on Scifi, or one of its commercials) is:
"I will face my fears; I will let them pass through me."