"Good Girl"

Do you say "Good Dog" or the like when you train your dog? Have you thought about what it might means to your dog? Many people say something like "Good Girl / Boy" to their dog to communicate that something the dog has just done was good, (liked by the owner). Most often we will give our dog some kind of reward (food, praise, fuss etc...) at the same time or after we say "good dog". If our dog always hears "Good Dog" after they get the reward, could "good dog" then not mean to your dog that all the good stuff has finished; Where as, if you say "Good Dog" first, as soon as the dog does something you like, then "good dog" starts to communicate to your dog why s/he is getting rewarded and therefore become more meaningful?