There’s a storytelling convention in TV and movie scriptwriting that I really don’t like.
If a dog — or a cat or horse, but most often a dog — is introduced into the plot, there is a better than 50-50 chance that the animal will die as part of the story. 
Occasionally this story convention works, but much of the time, it is quite gratuitous.
Because I feel particularly strong empathy with suffering pets, I immediately steel myself for the possibility that the animal will be killed off by saying (aloud): “Dog’s gonna die” as soon as I see the canine on the screen.
The most recent offense was on my beloved Mad Men. The dog isn’t actually killed, but if you let an Irish setter go outside of a Manhattan office building — even in 1962 — what are the odds? Poor Chauncey.
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I know what you mean. Trouble is the story of my life is so wrapped up with dogs (I have four snoring basset hounds under my desk, one of which is due to have pups in a week) that I can't help but project this kind of scenario into my own story! Dogs, alas, just don't live as long as they should!
But as we basset people say: bassets are angels with floppy ears!
Thanks for your comment, Jon.
I am very much reminded that dogs don't live as long as they should because today is my dog's 8th birthday. The idea that she may be with us for only 5 or so more years is almost more than I can bear.