In reply to Reggie Perrin:
The singing thing - 'Singing in the rain' for me, because it's eminently hummable, and tum-ta- tee-tummable.
I was once following someone across the Eastern Travers on Tower Ridge. Unbeknownst to me, he was gripped out of his mind. Sometime later, he thanked me, because all the while he was gripped, there was some bloke behind him, idly kicking the snow and humming Singing in the Rain. It helped him get a sense of perspective., apparently. The power of singing by proxy
Alternatively, random phrases have a place, for example -
"Oh, the jackpot
is in the 'andle
Of a normal fruit machine'
Ian Dury, which persisted for a week long trip to Scotland and made an appearance whenever moral support or levity was needed.