Well, I've had three collies and one sheltie and the Timmy in the well scenario describes it nicely!
My collies were not as driven to *always* be doing something as my sheltie. I refer to my sheltie as my little ADHD child whereas my collies were more 'hey, you're relaxing now?! Great idea, I'll come relax with you". My sheltie will persist in trying to get me up off the couch to do something until about the third 'go lie down!' when he'll go pout.
And while my collies apparently found it necessary to supervise my baths to make sure I didn't drown, my sheltie takes it a step further and tries to kill the water-monster coming out of the tap. Explain that one to me!