Anyone who has ever had a bet on the prestigious PLAYERS Championships at TPC Sawgrass knows the drill.
You've backed a player and all seems to be going well. But until he has negotiated the island green at 17, chickens can never be counted.
On the card, that 17th hole measures just 137 yards.
But being surrounded by water gives it a totally different dynamic. The wind can swirl, putting doubts in minds, and it's been the scene of several final-round disasters down the years.
Len Mattaice was just one back in 1998 but racked up an eight to ruin his chances of victory.
Davis Love, Scott Gump and Phil Blackmar have also seen their dreams shattered at TPC Sawgrass' devilish penultimate hole.
Galleries posted around 17 - and there will be some spectators at the famous Florida track this week - will spend all day making proposition bets on whether a player's tee-shot will find water or not.
And those who fancy a punt in front of the TV are also afforded the chance.
But which way will you go - land or water? Thankfully, the bookies cater for both personality types: the evil bunch cheering on disaster and the optimists seeking smiles of relief.
How they bet on the number of balls in the water in 2021
Bet365 are on the case and they've priced up the market like this:
Before wading in (perhaps an unfortunate term), to get a feel for the bet requires two things: looking at past records and what the weather forecast says for this week's action.
The wet count: how many balls in the water at 17 in the last 10 editions
2019 - 45
2018 - 54
2017 - 69
2016 - 36
2015 - 45
2014 - 28
2013 - 44
2012 - 39
2011 - 40
2010 - 29
(Note: the tournament was cancelled after 18 holes in 2020)
In terms of the parameters used in the betting markets, 48 & over has landed just twice although both were in the last three years; 37-47 has been the correct count four times and so has 36 & under.
On that evidence, 36 & under is value at 12/5. But what about the weather? A windy forecast and suddenly everything changes completely.
Weather forecast for TPC Sawgrass
Play starts at just before 7am on the first two days.
Thursday: The wind will be gentle at around 5mph for the early starters but the afternoon wave will have to deal with 10-11mph.
Friday: Sunny conditions are forecast, with wind speeds of around 5-10mph.
Saturday: For round three, read round two: sun and winds at 5-10mph.
Sunday: The temperature picks up slightly but winds could increase to 10-15mph.
Looking at historical weather, it really blew in 2017, hence the number of balls (69) in the water. But there's nothing extreme this time so it may be worth backing both 36 & under and also 37-47 inclusive. They're combined odds of just under Even money and the bet would have landed in eight of the last 10 years.
Perhaps there is an even better bet for optimists.
Rather than cowering behind the sofa, willing every ball to finish on dry land, how about actively cheering on the ultimate postive: a hole-in-one.
We've had nine hole-in-ones on the 17th hole in the history of the tournament and five of those have come in round one.
So, head over to William Hill and back the 4/1 for a hole-in-one during Round 1. It's the same price as Round 2 but it shouldn't be.