I learned a fascinating thing about wine-making in South Africa recently.
Winemakers press the same grapes several times. The first pressing gives the best quality wine, and the last the worst quality (much the same as "extra virgin" and "virgin" olive oil). The interesting thing that the winemaker I spoke with said was that by law he is not allowed to throw any wine away - all wine produced has to be sold.
My first thought was one of admiration for the law-makers, as I figured they must really appreciate the value of a good bottle of wine. This naivety was quickly dashed though, as the winemaker elaborated, explaining that it's not for any environmental or other good reason, but because the government wants as much tax money as possible.
A wry smile what all I got when, in an effort to save us all from bad wine, I asked why the last pressing of poor wine wasn't simply skipped. From his response I gathered that plenty of very juicy grape skins are disposed of each year. :)