There are few things that are guaranteed to so quickly make me smile as coming across a sleeping dog: in a patch of sun or shade; on a doorstep or in front of the shop where they get a regular meal, by a patch of gravel. They are completely relaxed and in the moment; in a word, adorable: I hope they bring a smile to your face, too.
Also wonderful - reminds me of my time in the old city of Sana'a, Yemen, where dogs would sun themselves on the roofs of cars during the day and roam the alleys in packs at night.