Mouthy dogs are more likely to use their mouths to hold or "herd" their human family members, and they need training to learn that it's fine to gnaw on chew toys, but not on people.
Mouthy breeds tend to really enjoy a game of fetch, as well as a good chew on a chew toy that's been stuffed with kibble and treats.
Obedience training and interactive dog toys are good ways to give a dog a brain workout, as are dog sports and careers, such as agility and search and rescue.
See Dogs That Have Low Intelligence Common in most breeds during puppyhood and in retriever breeds at all ages, mouthiness means a tendency to nip, chew, and play-bite (a soft, fairly painless bite that doesn't puncture the skin).
If you've got a laid-back attitude toward slobber, fine; but if you're a neatnik, you may want to choose a dog who rates low in the drool department.
See Dogs That Are Not Big Droolers Some breeds are brush-and-go dogs; others require regular bathing, clipping, and other grooming just to stay clean and healthy.
If you're a neatnik you'll need to either pick a low-shedding breed, or relax your standards.