Why do people think bloodlines are such a big deal?

I don't think bloodlines matter either. But people do it because some horses are rare, and their bloodlines matter, and to raise the price of the horse also. If i see a horse i like, i look at it, i don't check for its bloodlines. I look at its color, then maybe if i can, i could actually see the horses personality. I don't judge horses, they are all perfect in my eyes, from purebred to none purebred. If it's a horse, i love it! :D