New to puppy/dog world?

okay i feel like an idiot but i have to ask, what does BYB stand for, it is as i have noticeed always used in a sentence that make it seem that it is not good, i got my yorkie pup from a pet store and i am betting that it will be called a BYB, and yes i have had nothing but problems, but they are not hereditary problems so far, stupid problems on my part actually, and i did homework for a year on this breed before buying him, but nothing prepared me for the real thing, all the problems my little guy is having i never read anything about.