Swirling a glass of wine then looking intently at the glass and commenting on how great the legs look on a particular wine makes you sound like you know what you are talking about and opens the door for yet another sly double entendre at a cocktail party. But alas, those legs don't quite mean what you think they mean - in either sense.
Those "legs" or the less sexy name "tears" dripping down the inside of a glass of wine are simply an indication as to the fact there is alcohol in the wine. More legs indicates more alcohol and not much else. If you measure a wine's quality by the level of alcohol in the wine those legs might mean something to you. But if you measure a wine's worth by what it tastes like, then... Open up and say ahh.
If you were interested the nerdy explanation for wine legs follows below.
The scientific explanation for wine legs is a result of the varying evaporation rates and different surface tensions between alcohol and water (The major components of wine.). The wine crawls up the glass as you swirl it because alcohol has a lower surface tension rate than water and pulls itself up the side of the glass. Then as the alcohol evaporates faster than the water, because of its lower boiling point, the water forms droplets and falls back down the inside of the glass. Or something like that.
Drink what you like.
