The difference between our cats and our dogs

Three Shelties playing on the couch - with the new big boy waiting his turn to join in.  This is a typical scene in the house - at any time a dog pile could start if anyone is in the mood to play.

Contrast this with most views of our cats - lazily curled up in a warm place anywhere in the house.  If any of the cats happen to be in close proximity to another, this is by coincidence rather than by design.  Playing with another cat...not a chance!