William Goldman, the renowned Hollywood screenwriter, once said of the movie industry: "nobody knows anything."
The same can be said of sport. For all the endless punditry, sport is about human emotions as much as the formbook. It's about seizing the chance.
So for all the predictions, anything can happen. This was certainly the case for Chelsea against Barcelona last night and is increasingly true of the Betfred.com World Championship.
Andrew Higginson seized his chance well against Stephen Lee, the most consistent player since the turn of 2012.
Lee won what looked like a big frame to close the gap to 7-6 at the interval, enjoying a few slices of luck in the process.
But what happened next spoke volumes for Higginson's attitude. Instead of spending the interval down in the dumps he reminded himself he was still in front, made his first Crucible century and won 10-6.
Even after he lost 5-4 from 4-0 up to Ronnie O'Sullivan in the first round of the German Masters, Higginson took the positives. He felt he had played well and refused to get on his own case. A few weeks later he reached the semi-finals of the PTC Grand Finals.
There are enough things that can go wrong in snooker, and more than enough people who can beat you, without you having to get down on yourself. Higginson has got the reward for accentuating the positives.
O'Sullivan came through rather tamely in the end against Peter Ebdon but from ten results, five seeds have lost and several more are in trouble.
Judd Trump woke up yesterday with food poisoning. He was seen literally being sick in a Crucible toilet.
He looked pale and in pain but creditably came out 5-4 up on Dominic Dale.
Ding Junhui resumes in touch with Ryan Day, trailing 5-4, but Mark Selby, who has barely practised since withdrawing from the China Open with a trapped nerve in his neck, fell 6-3 adrift to Barry Hawkins in a session which ground on, and on.
Graeme Dott's performance was perhaps the biggest surprise of all. The 2006 champion hasn't had the best of seasons but the way he played against Joe Perry must have been a desperate disappointment.
When you are getting ironic cheers for winning a frame, as Dott did in the ninth, you know it isn't going to be your year.