The Boston Terrier’s sweet nature and popularity in the States has seen them become known as the ‘American Gentlemen’ of dogs. In fact, these dogs are so friendly that they can absent mindedly wander off with the wrong person so it’s good to keep them on a lead when you are not in an enclosed area. Because they are brainy little dogs, they are easy to train and should be kept stimulated through interactive toys when left on their own. Celebrity owner: LeAnn Rimes.