At a horsemanship clinic I learned something quite interesting. The more relaxed your body posture and actions are around the little darlings, the more comfortable and confident the darlings are. I watched a demonstration of this where the clinician approached the horse like a full bore slobbering,messy, staggering drunk, crashing up against the horse, banging into thehorse - it didn't bother the horse even a little bit. Then the clinician simply changed his position to an upright "I am going to visit you" posture and the horse went on alert. He wasn't scared, but he wasn't totally relaxed like he had been either.
And do you remember when you rode as a little kid you did all kinds of crazy things and didn't get hurt? As in 3 or 4 of you setting on his back, crawling between his legs, running full bore out, jumping up and down, and screaming all around the horse - and it didn't phase the horse even a little bit. Why? Because kids are not yet predators and they just really don't care what the horse does.. And, when I say predators, I mean "goal-oriented". Kids become practicing adults around 10 years old or so, or when they enter shows and competitions - they then have a goal in mind - and that makes everything different for the horse. Now he has to comply with their wishes, pay attention, be on alert and be obedient - all very different than hanging around kids and drunks.