Horses, being horses, love to test us periodically. My one boy will decide he's leaving, not in a hurry, just Na na, I'm not letting you halter me today. All I have to do is begin to circle around and he'll immediately turn and give me his full attention. If I back up a step or two he'll approach and stand as I approach from the side. I will rub my hands on his shoulders and back, like a mare licking her foal, then his neck and slip the rope over his neck. I don't catch the end as there's no need, and then I slip the halter on. I have found that the more I drive him away, it's now like shooing chickens, the more he wants to be with me.