Bad cell phone service
One of the most desirable characteristics of a music festival is the idea of an escape. Run into the desert with a cape and enough bacon for three days. Take a ferry out to an island, go deep into the forest where no one can hear or see the excess and glory that is nonstop music consumption. But then somebody gets lost, and you realize this beautiful mountain vista has left you without any shadow of a cell signal, so that person you lost—maybe it's you—is on their own. And that sucks when your sober and alone. When you're inebriated and know that all your friends could be at the best show of the weekend? Well, that's a first world problem of the highest degree.