Here is quote from and a link to a really great article
1/29/2016 at 3:26 PM
"Remember that pets live in the moment. One of the most wonderful things about animals is how they embrace the present. Every time I walk into my house, my faithful Vizsla throws a one-dog ticker tape parade. The fact that I have entered the house thousands of times before, or that I will leave again in a few hours, means nothing. All that matters to him is the joy that he feels right now.
When our pets are suffering, they don’t reflect on all the great days they have had before, or ponder what the future will bring. All they know is how they feel today. By considering this perspective, we can see the world more clearly through their eyes. And their eyes are what matter."
http://www.vetstreet.com/our-pet-experts/how-to-say-goodbye