What this restaurant didn't seem to understand is the fact that groupon is like any other promotion. It's a loss leader that brings in new business. Perhaps the groupon customers wouldn't have been so bratty if the deal had been worded better, but who knows. The thing is that places like restaurants rely on repeat business and word of mouth as their primary sources of customers, and that's what groupon is designed to bring. I think the fault here is not in groupon's hands but the restauranteur.