Betting. You only ever hear about the winners, right? Your mate Dave - who won £457 from a fiver by betting on Manchester City, Newcastle, Millwall, Hartlepool, Portsmouth and Polish third division side Odra Opole - didn't tell you about the previous £500 he'd lost to get to that point.
You may think that was lucky, in fact you'll probably tell him he's a jammy shit right after he's bought you a pint with the winnings (yeah right, Dave's pocketed that cash for himself).
But something even more flukey than that would be the guy in America who correctly predicted the first four finishing horses at this year's Kentucky Derby.
The horse race, held in Louisville, Kentucky, on the first Saturday of May each year, sees horses run for 1.25 miles and is known in the US as 'the most exciting two minutes in sport'.
The one dollar payout for predicting the top four was a tasty $75,974.50 (£58,726) - that's double the UK's average annual salary.
Predicting the top two by betting just one dollar would have netted you $118 (£90), while the top three could have seen you line your pockets with $8,297.20 (£6,413).
One man felt cocky though and went for the 'superfecta' - a stake on calling the first four horses home. Indeed, as he predicted, in came Always Dreaming, Lookin At Lee, Battle Of Midway and Classic Empire.
The odds on the winner were only a measly 9-2, but second and third had odds of 33-1 and 40-1 alone, respectively.
Obviously, as the price suggests, the odds on calling this are slim, very slim. Mind you, the bookies got a let off this year. The $75,000 jackpot is quite low considering in 2009 the superfecta paid out $557,000 (£430,548), and in 2010 it was $202,000 (£156,141).
In fact, the lowest payment between 2007 and 2014 was $15,383 (£11,890) - and that's still not to be sniffed at.
Only last month, one bloke smashed the bookies this side of the Atlantic - in fact, it's Coral's biggest ever horse racing pay-out.
His £19 on just five horses saw him bring home the bacon with £823,000 winnings. He'll forever be thankful to Punchestown Racecourse and will probably name any future children after the horses.
Featured Image Credit: Twitter/PA