man, it totally pays to complain. this past weekend in DC we stayed at this hotel called L'Enfant Plaza Hotel. It was a 4 star hotel that we got a good deal on from Travelzoo. $109/night.
so there were all these little issues, like we got two doubles beds instead of a king bed, the tub was clogged, random stuff.
so i wrote a stern email and we got two nights free in a better room! woohoo!
(I really liked the location of the hotel because the metro was right below us so we didn't have to drive anywhere, so that's why i requested a free stay rather than a refund)