One reason I'm glad I'm not a dog is that I hate the taste of fresh tennis balls. Have you every tasted a fresh tennis ball? I have.
I won't go into the details (although it's very similar to a tense scene in
Pulp Fiction) but it's not pleasant.
I'll admit, there are lots of good reasons to be a dog. Sleeping all day. Not working. No responsibility. But then there's the obligatory tennis ball retrieving. Can't do it.
I prefer chasing my wife's meatballs. Much tastier. Which is why I never return them to her.