It's a mostly-silent new-run that has Mike and Liz wearing Farley out playing.
Panels 1-6 We see Mike and Lizzie lots of fun playing with Farley.
Panel 7: Too bad he's a puppy and needs more sleep than they do. They're still having fun and he's zonked.
Panel 8: Watching him lay down in his cage sleeping has wiped the smiles from the kid's faces. They probably realize that they did this to him and feel bad.
Panel 9: Elly thought-bubbles that she was wondering which of them would get tired first. Poor Elly; listening to children play is soooooooooo tiring.
Punchline: Elly thinks children should sit quietly with their hands folded staring into space all day long and puppies should be content to stay in their cage.