I think the having to leave him part. LOL. I don't really like to leave him, and would love if he could always just be with me but, well, life happens and he can't be with me 24/7. But even when I really want to go somewhere and go away and have fun, I always have him in the back of my mind, and it makes me want to get him sooner than I would if I didn't have a dog to get home to, ya know?