"Many people lack the self discipline necessary to be really great with horses. What Iím talking about is ownership of everything that goes on. Everything that goes on with your horse, from the time that you head to get him from the pasture in the morning until the time when you release him to graze again after a dayís work, is your responsibility. You own it. If it goes well, if it goes poorÖ the good, the bad, and the uglyÖ itís all yours. I tell riders in my classes, If your horse kicks another horse (in the class), itís your fault for not recognizing that shaping up and getting your horse doing something different. If your horse gets kicked by another horse, itís your fault for not recognizing that shaping up and getting your horse doing something different.
You own everything that happens when you are with your horse. You canít blame somebody else or their horse for your frustrations. That other person usually has enough trouble handling their own problemsÖ they donít need you adding to their pile. Just deal with what you have on your plate." -Patrick King, horse trainer
I completely understand your frustrations with that horse's trail behavior. Maybe your friend could benefit from the above quote...? I think I would rather ride alone than deal with that, best friend or not. I know my riding time is valuable to me and I want to make the most of it, not worry about falling off a cliff!