Twisterdog, wow! Powerful words. Really something to think about. Helps a lot of us who have had or will have to make difficult choices put things more into perspective. Sometimes, because our pets become such real companions - people- to us we think they can think and reason the way we do. If you ever watch a dog dig a hole after he was just punished for doing so or watched a dog eat all the food that is there never worrying about would there be more for tomorrow or run away not knowing sure if they will know their way back, you know they do not worry about things the way we do. They live in the now, the moment. I am not saying we should put dogs down randomly because whatever we gave them was enough, but when a dog has some major problem and there seems to be no answer that will not mean much more pain or a fix that would enhance his life, we should not feel guilty that we had to make a choice that we did not want to make.

And as you so aptly put
They have no concept of mortality, death, fairness or fate. They just ... are. It's all good to them, whether it is short in our eyes or not.
Thanks, Twisterdog!