One time, I went to a birthday party my mate threw for his wife. I took her a bottle of expensive Champagne, and she said they'd save it for a "special occasion".
The night before, she'd been out with all her friends to a club and as it was her birthday bash the DJ had given her six bottles of cheap, fizzy plonk.
Half way through the party night, my mate was off his trolley, and was going around topping up everybody's glass with this cheap plonk (including beer drinkers).
Half an hour later, he was going around topping up everybody's glass with the expensive stuff.
I've never let him forget it.