Even if the "OP if is a troll", this is an interesting topic.
Being a catch rider in college and having a young opinionated greenie, I completely agree with the MIE's statement. However, I also agree to some degree with the idea that if a horse doesn't like something, they're going to do it anyway BUT the rider has to assess the situation and determine what's appropriate. If the horse is being a jerk about crossrails and crashes through them at the trot because he's lazy and saying "no I don't want to do this", (and NOT "no I can't do this because this is too physically difficult") that's a totally different situation from a horse disliking his discipline and saying "no I don't want to do this".
Again, my horse can be very opinionated, and my trainer offered the idea that at stages where the horse says "no" or is unsure of himself, primarily ask questions that you know you will get a response of "yes, ma'am!" and slowly build up these questions until you can start asking the more difficult ones with a higher success rate. ;)