Labradors and Goldens are indeed the two "poster breeds" for guide dogs! I've also seen other breeds like German Shepherds and Poodles - any intelligent working breed can do it, but it's best that they not be too energetic. And service dogs have "off hours" where they're "on break" and get to play or chill out if they want, just like any other dog, so no need to worry, Haru-san!