Inbreeding is responsible for a lot of the issues that many purebreds have but that ' s only been a serious problem in the last thirty years or so as commercial breeding has become a serious moneymaker . Once people started breeding for sale , not function , and it didn ' t matter that the dog only lived five or eight years because of health problems because the puppies still sell for thousands apiece , then major health problems became common . Pugs look very different today than they did in the early 20 th c , the popeyed flatfaced look is much more prevalent because that ' s what ' s cute and what sells . Think about the giant breed dogs that live only 58 years because they ' re sixty pounds heavier than breed standard , but sell to to people who want huge dogs . The craziness that is the English Lab , which doesn ' t exist in the U . K . but Americans love Labs that are over 100 lbs . Or GSDs that suffer horrific arthritis because the crouchback look is badass . Or corgis and Doxies that have to be put down because their backs are too deformed to support their weight for more than eight years or so . Weimaraners and Huskies so neurotic they ' re put down because they won ' t stop barking or chewing themselves or biting anything that come near them . All problems that arose within the last thirty years .