I just want to add that, as a rule, I always hold the lead rope not in circles around my hand, but layered (if that makes any sense). I don't want the horse spooking, tightening a coiled rope around my hand or arm, and dragging me off just like the barn door. It's really easy to loop the lead around, but I was taught never to do it.
I prefer those safety clips when horses are tied that hold, but when pulled hard, release. I'd rather have a loose horse than an injured one.
Personally, when I let a horse graze on the halter, I pay attention to that, not do two things at once. I think horses are a one small step at a time creatures. I hate leaving a horse in the cross ties too, even if there are other people there, it just makes me nervous.
I have never had my own horse, but always worked for lessons, so dealt with many other people's horses. All different, different manners, reactions, everything.... But the one thread through them all is that they're unpredictable.
The mare I was riding this morning was neighing a l as I took her out of her stall, and even as I got on and rode her. That makes her a little unpredictable--I found out she's in heat. I've been on a mare in heat, and had a rather, um, uninformed gelding break out of the pasture, come down a road into the riding arena and try to mount her. Yeesh.