When I do complain, I try to put as best a spin on it as possible. For example, I recently flew US Envoy and felt the service was a bit lacking and also made a couple of suggestions. I got back a letter from the Executive Office of Consumer Affairs that specifically addressed my concerns and said they had passed on my recommendations. Anyway, I digress slightly, in the letter I made sure to say that the reason I was writing was in hopes of my concerns being addressed and the service being better next time I fly Envoy.