There are people today that have developed this bond for their dog or cat....and frankly, it's the only true relationship that is balanced (all in favor of the cat or dog).
I had an associate once point out that when older relatives come to visit for weeks or months....you start to have issues. Your bonding to that older relative isn't quiet the same. When you do special things for them....you really don't put significant regard to the quality.
My associate then pointed out that as our pets grow older and fall into this same category....we readily volunteer to drive five miles to pick up special dog bones for our 10-year old collie. Or we spend an hour combing the ten-year old cat because it's the right thing to do.
When the older cat begs for attention, we readily provide it because they've given something in return that isn't measurable. When the old dog begs for a walk in the middle of snow, we get up and do it without thinking.
Our pet is more than a pet. They've become a friend that we can't imagine being without. We won't admit that to anyone.
So enjoy a good five minute read with USA Today and this article.