My golden retriever and I frequent a huge, hilly open meadow a in Prospect Park called "the Nethermead." It's a wonderful part in the center of the park where no buildings are visible, and it is quite easy to forget you are in the middle of one of the largest cities in the world.
There are two dogs often there who can only be called best friends. One is a doberman, the other is a pit bull mix. They are about the same size and weight, I'd guess, although they have very different shapes. They share a toy that is a big rubber ring, about 10 or 12 inches wide. Each dog grabs one end and pulls. And so they tug, face to face. For hours. It's like watching an eight-legged dance across the grass.
"Who needs TV?" I asked, the first time I saw them. They can keep each other entertained for hours! They are perfectly matched, fully engrossed, focused only on each other, working hard and going nowhere.
This reminds me of couples who are deeply engaged in fighting with each other. It can be very engrossing, taking all of your attention, and require constant adjusting and maneuvering -- but look where it gets you ... nowhere!