Personally, I've never fully understood the appeal of picnics. My image of them primarily comes from memories of going to Fourth of July pops concerts in Chickamauga Park, hauling coolers and blankets to whatever tiny patch of open ground we could find on the crowded hill, and listening to the 1812 Overture under the stars with cannon firing on the other side of the tower. The food was never the starring attraction; it was really good (my mom's potato salad with the slices of hardboiled egg on top particularly), but I always thought it would be just as good indoors and I'd worry a lot less about wind, rain, bugs, and dropping my plate.
Now that I'm all grown up and no longer under the roof of teetotalers, I understand picnics a little better. A glass of wine as the sun goes down and the breezes blow certainly has its attractions. But I see a clear distinction between eating outdoors and drinking outdoors. Is there any food that is enhanced by an alfresco setting, the way a nice flowery white is? Isn't it, I posit to you, beverages that we really want to consume out on the open, rather than entire meals? Is there any liquid comestible that fresh air does not improve, from tea to pale ale?
Perhaps your picnic experiences are more food-centric than mine. If so, I'd love to hear counterarguments to my bold assertions about open-air drinking!