I think Bailey said it best when he explained he always had a plan and always knew that he could find himself in multiple situations he did not expect to be in. Then decisions must be made. If your horse loses with a decision, you are an idiot. If the horse wins, brilliant.

But on the side of Scuds... Some horses clearly must be ridden a certain way. If the jock tries to be a control freak, it can lead to a bad situation. The most common thing I notice is the strangle hold a horse on the lead often gets. Some horses obviously run incredibly inefficiently while choked and not only does the jock slow them down, he actually tires them out more. It is the trainers job to correct this situation. Some horses just have to be let loose during a race though, you just kill them holding em back. We all heard Baffert's comments on Sinister Minister. Sean B. is the master of the inefficient choke hold imo.
I think the better jocks have body language other than the reins that tells the horse not to panic and then they can get the horse covered up and running in comfort if the horse wants to run away. (Somtimes this clearly does not work either)And most of the younger, very fast horses want to run very badly.
Take a bunch of elementary school kids, line em up on the track and send them around one time (~400meters) in a race. The fastest kid invariable gets beat. Kids are smarter than horses.

Scavs. When the Frenchman got thrown by that horse over the rail at Keeneland I swear the horse was so tired of getting beat he hit the rail on purpose. The horse was dead tired and just had enough.