Well said, Klim.

I love me some horses, and would, at times, feel like they kind of liked me. Among lots of other horse jobs, I've worked with draft horses... spending all day together you do get a sense of closeness. Those big guys are pretty laid back by temperament and breeding, and every effort has been made to acclimate them to scary things so you don't go on a Nantucket sleigh ride if they hear a car horn, see a hot-air balloon, or any of the million things that could disturb the inscrutable mind of a horse.

Even with all that work, you have to assume something will freak them out. This means that even with the mellowest old horse, you don't step between the horse and whatever equipment they are chained to. You don't hang out where you could get kicked. You be sure not to be connected, or potentially connected, to the equipment they're pulling. You don't leave the reigns, and you don't have the reigns wrapped around your wrist. And you sure as fuck don't get wrapped up in a horses leg as seen in this picture.

These young horse-crazy girls can form some amazing connections with their horse-friends, and I think they are loved back. But horses have freaky little anxious pea-brains largely devoted to not being eaten by things that jump out from behind bushes or otherwise surprise them... and you can never know what they will consider threatening and when exactly they will need to drop what they were doing and tear off at an equine warp nine. And G-d have mercy on your soul if you happen to be wrapped up in their massive death-pistons at that time.

That said, this is a touching picture!

edit: I was considering your great dane analogy. There's something about dogs which seems more loyal, on average, than your average horse. Horses seem less ready to sacrifice themselves, and less aware that they will kill you accidentally than dogs. [Not including dogs which are trying to kill you, of course.] Horses are flighty and unpredictable, and this becomes a problem with the ones you get used to being bomb-proof. Because they're really not, when the wrong stimulus comes along.