The best thing are 1 star ratings without an explanation... There should be a requirement by Google to write something if you rate that low because there has to be a reason (even if its something like "I don't like your face") - otherwise how do you expect me to make it any better?
Well, even if a "reason" is being given, it's not helpful more often than it is. Stuff like "controls suck" doesn't help, but at least you can ask for more details (which you usually don't get). Stuff like "It's a f****g wh*** game written by the queen of f****g wh***s" (without the *, of course) helps even less. Then again, some people do post helpful reviews or even send you a mail with more details if you ask them.