I have a 7 year old 15.3 hand Quarter horse that I purchased a few months ago. At his previous home he was being trained for hunter under saddle, and I got to watch someone else riding him and he looked really good. Ever since I got him he just has not been the same- although since I first got him I've gotten to him lower his head and stride out much more at the trot, he still sometimes becomes very anxious and trys to trot really fast and unbalanced. And he's worse at the canter, he's usually strung out and fast. Sometimes, though, I can get good, collected gaits, but not always. I would really like to show him in pleasure classes, but I am having problems with him being fast and anxious sometimes and not moving like a hunter under saddle horse. Also after cantering when I've asked him to walk he'll try to speed back up again and really pulls on my hands to try to go faster. I know he can do better than this, I've seen him and I've experienced some of it myself. Is is just something I'm doing wrong? How can I get him to relax, slow down, collect, and listen to me all the time?