My paint gelding has been my partner in crime for years. He was started well, I bought him as a 4 yr old, and we are to this day limitless to what we can cross, climb, open, or close. However, I know that with him, it is training. He trusts me completely, but he owns those skills through training. He has always had courage. I know that if I put anyone on that horse, he is capable of holding their hand and showing them how its done. After which, he will look at me, and give me that "get this person off my back before I rub them off on a tree look". I know that as well trained as he is, he is and will always be my horse.
In another case about 3 years ago, I stumbled upon an add that said "3 yr old appendix mare, $200". It was nearby, so I checked out this 13.3 hh "appendix" (seriously doubt it). She was wormy, underweight, and had horribly overgrown feet along with skin problems. She had been through the auction and her current owner was terrified of her since the pony had chased her out of the pasture on more than one occasion. It sounds corny, but as soon as I looked at the little fillies face, I knew she was coming home with me. The pony that didn't load well walked right in my scary little trailer. The first time I worked with her she reared straight up and started coming at me, once that was resolved the first time, she never tried anything again. Since then, she's ridden in parades, done pony rides at events, walked right up to and looked at the face of the man on stilts, and will go wherever I ask her to go without question. As willing and sain as this pony is with me, she will freeze up if I am not there. My goal with her is to help her to own her skills so that she doesn't always insist on following my lead. I have had multiple trainers comment on the extreme trust that the pony shows to me alone. I know for a fact that her skills are not training related, as I contacted her original owner and she had never been broke prior to sending her to the auction. The people I bought her from attempted to ride her and the petite pony managed to buck the person off. The first time I got on her, I rode her a couple miles off the property bareback with a halter and a lead rope by herself. Not something I usually do on a first ride, but the mind and willingness the pony was showing me was irrisistible.
I have always been the first person to say "well yeah, they are trained for it", and the first to roll my eyes when someone says "my horse only loves me". Now, I still think its is related more to the fact that they will go where the lead horse says to go. Any horse that I see resisting is also a horse that is still testing the leadership. I don't think my pony has a magic bond with me by any means, but she thoroughly trusts my leadership over any other.