"That's a lot of dog in a small package."
"I think he might be too much dog for you."
"You don't have much dog to work with."
Has anyone said anything like this to you? What on earth does it mean? How could one 50-pound Shepherd mix be "too much dog" and one 50-pound Shepherd mix be "not enough dog?" How can a Chihuahua or a Pomeranian be "too much dog?" And anyway, who's to say what's "too much."
The amount of "dog" you have has to do with your dog's energy level, motivations, drives, and more. A "lot of dog" is typically a very physical, energetic, highly motivated dog. And by "highly motivated," I don't necessarily mean "highly motivated for obedience." Usually they're highly motivated to do things like play, investigate, steal stuff, drag you around, etc.
These are the type of dogs who happily and easily develop terrible habits if you aren't careful. Always looking for a way to entertain themselves or access things they want, they are also very insistent on doing things their way. They're very smart. They're very active. Think of breeds like the work-aholic Border collie or the overly-eager Lab.
On the other hand, what does it mean for a dog to be "not much" dog? Usually this is a slower-moving dog who's more inclined to pause and calmly take in the situation rather than plunge right in. They are not particularly motivated by food or play -- they might eat a tidbit or follow a ball, but they're not willing to work very hard for it. They tend to have excellent manners -- who doesn't love a dog who just sits or lies around calmly, and never pulls on the leash! -- but it's hard to get them going enough to do more difficult or active training tasks, like go-outs or retrieves.
Any individual dog can have varying levels of "dog" at different times of the day or in different environments. (For example, don't expect much dog in very hot weather or at the end of an intensive obedience class.) It's common for dogs to begin training sessions as "a lot" of dog. The smart trainer will channel all that enthusiasm and energy into doing the correct behavior, and not exhaust, confuse or overwhelm the dog (doing this can give you less and less dog during the training session.)
If you think you might have a lot of dog, great! Here's some things that can help you channel all that energy and drive: Some light exercise just before a training session might help. Start your training with active, exciting exercises such as heelwork or sit/down/stand drills. As your dog begins to calm and focus, switch to "stay" or other less active exercises. Use toy rewards as well as food rewards; however, when you are not rewarding with play, be very clear to your dog and use a calm, consistent tone of voice. Try to have a plan for each training session as you go in; this will help keep you and your dog on track.
If you find yourself in a training session with not enough dog, don't give up! These dogs benefit from much shorter training session. Even a few minutes of training at a time, several times per day, can warm these pups up and get them craving more. You might be tempted to "cheerlead" your dog (bright, happy chirping "Good girl! Good heel! Good girl!" etc) during training, but this often doesn't help at all and instead just shuts the dog down further. Start out matching your energy level to your dog's energy level, and then increase your energy level up just one notch. Don't overwhelm or you will make it worse!
You will soon begin to notice, on a day to day and even moment to moment basis, "how much dog" you have at any given time!