Power
Napoleon was a man with great power who liked horses.
You, however, are not Napoleon, even if you're close to his height and share his affinity for powerful four-legged animals.
There'll definitely be some power you'll have over your horse. From the hardest slap of your whip to the slightest tug of the ear, every signal you give the horse will tell it what to do. But even some days you just won't be able to tell your horse where to go no matter how hard you try. While you may be the most gifted jockey in all the land, if the horse doesn't feel up to it, there's not a whole lot you'll be able to do.
Your power within the organization is fairly limited, too. Unless you're a big-race-winning jockey with a great agent and an endorsement deal and a horse racing video game, you're basically just the person they strap on the horse's back for balance.
If you win, they'll pat your back and shake your hand, and then they'll take the horse, trophy, media attention, and most of the money and leave you standing there wondering what happened.