Don't let people like that get to you. For the 2 seconds they are in your life, it is not worth your trouble. I wear a baseball cap or hat to help me keep my mind focused and to help me block out negative attention from my mind. Sunglasses or transition lenses are a good idea too. Personally, I like to chat with my servers whenever possible. If I find that if they are able to accept my flaws and silliness, then I am sure to reserve a warm smile for them. Most appreciate me for that and most are warm and sound enough to reciprocate.