Read all about it
This is an issue close to Michela's heart. Having adopted nearly every dog I've ever had from a local shelter, and been rewarded in spades with a happy, healthy, wonderful puppy dog, it sickens me to think of people who propagate the pure-bred dog industry. The results are discussed in this article, and they're disgusting.
Puppies are taped to speaker boxes, strapped to the underneath of car seats, crammed into boxes, and smuggled across the US/Mexican border in hot cars. They're bred in horrific conditions, and shipped across the country by heartless, ignorant buyers on the internet.
How can anyone with a conscience buy a dog? The likelihood of the source being some idiot who bred animals in family lines that are too close is big enough; you're still going to get birth defects. That's nearly your best-case scenario. In the worst-case, your new dog comes from a puppy farm, or a Mexican street breeder, and had a brief life that would pass for a horror movie, like the article says, if only the poor doggies could talk.
So when you get a dog, and you end up with large vet bills and a broken heart, you got what you deserved. Too bad the doggie got what he got, and deserved nothing of the sort.