...and I have one that is not the size of a puppy, but barely over 2 years old, still acts like a puppy.
Keen is a greyhound we rescued from the tracks. He's good for me because he gets me out of the house when I would rather just sleep, but that's exactly the reason I don't love him with my whole heart.
It is lots of fun to watch him run when he' off leash, though.