Amber, people who breed to improve the breed as a whole. Not people that "love" Yorkies or "love" their babies and "wouldn't do anything to hurt them, but my female's in heat, when can I breed her?" That means people who breed to standards (not from what they've read in a book. More like what Lady Hawk said), and do ALL the appropriate health testing before ever breeding. The breed as a whole, each precious Yorkie out there, and every potential/current Yorkie owner DESERVES that. To do less is a disservice, and I'll hold to that because my baby and I pay the price for breeders who didn't care enough.
I'm not here to inflame people or make it difficult for potential breeders to ask questions, but I am here to advocate responsible, ethical breeding. Every Yorkie owner should recognize that even where they buy from affects the Yorkie breed, because the more BYBs and puppy mills they support, the more Yorkies are going to suffer. It's not about "ugly" Yorkies or pet quality vs. show quality, it's about HEALTHY Yorkies with beautiful temperaments and good structure.
And a big THANK YOU to you breeders who are still learning and doing all you can to keep improving. Much kudos.