We have one in DD's dance company -- actually it's the mom of one of the other dancers. When I describe her to my friends I tell them she makes Debbie Downer seems like a party girl. This woman is always complaining about how much time the classes take, how much money it costs, how much homework her DD has, how her DD has hurt herself yet again (I think her DD must be the clumsiest dancer in the world -- according to the mom, this girl is always falling down and hurting herself), how bad she feels herself, how bad the weather is (even when it's beautiful), how her husband is out of town once again and she has to drive everyone everywhere, and the list goes on and on. I used to try and be polite and carry on a conversation with her, but now I mostly tune her out and just try and interject an occasional "that's too bad" or "what a shame" once in a while.
The mothers of all the older girls in the dance company tell me how bad they feel for me since her DD and mine are the same age, so at conventions and competitions, they're both in the same classes and I get to spend all day with this woman. My DD and her DD are both 10, so the dance instructor encouraged us to purchase observer badges and stay with our DDs, I probably would have anyway, but it was almost like undergoing torture.