Although, it might be important to be successful at shows (or with whatever it is that you do with your horse), you will never be able to reach the top if you don't have a solid relationship with your horse.
Your horse has to be able to trust you, and you him.
Respect is also important and it goes both ways. The horse must respect you as its leader. You in turn must respect the horse (it is a live breathing animal with emotions and feelings). Trust and respect goes hand in hand with one another. Which one you have to earn first, depends on the horse. With some horses, usually the more skitish types, you have to earn trust before you can get the respect. With other horses, usually the more dominant types, you have to earn respect before you can get their trust.
The stronger the bond with your horse, the more successful you and your horse will be. More importantly, the horse himself will feel more at ease.