I ride one horse for lesson and I feel perfectly stable on her even when she has spooked but on the horse my daughter and I half lease I feel like I am constantly trying to keep my balance. It feels like he is never quite right under me. We have been trying out horses for prospective purchase and the vast majority feel like the lesson horse even some of them that were too hot for my level of riding. I have been taking lessons 1 time a week for a year so I am a begginer and I am assuming it is me, but I can't figure out why one horse and not most of the others. Any thoughts?