You fancy the wine, but don't want to gamble on a crate of 24 bottles at £1mil a bottle.
So you agree to buy one bottle for £2mil and pay another £24mil on top if you like it.
The vineyard like the deal cos they stand to gain more than the £24mil original price. Plus, if you don't like the wine, they get to sell the rest at £1m a bottle to other customers and come out £1mil to the good.
You like the deal cos you get to try the wine before having to shell out a whopping £24mil. Yes, it might cost you a bit more in the long run, but the premium is worth it as the gamble is reduced to almost nothing...

