I've long since accepted the necessity of form letters for rejections; in fact, in most cases, I prefer them. (Except for that "We can't tell you exactly why, but it probably sucked" letter that Asimov's uses.) But that being the case, it would be nice if certain markets wouldn't stuff my SASE with other stuff besides the rejection. The resulting thickness of the envelope makes me think, "Hmmm....could it be? Could this be a contract? Ooooooh!"
(Yes, this is a stupid thing to complain about. My New Year's Resolution to whine less is not in effect yet. Oh, and there is no such Resolution. Heh.)