At times riders assume their horses are misbehaving when they do not respond to certain cues. To progress with the horse/human relationship, we must overextend ourselves to try to view things from the horse's position. Let me assure you that horses are overextending themselves to try to understand us!
Sometimes horses are uncomfortable with their surroundings. These feelings will inadvertently override cues that are being given at the same time. The rider should be aware of the horse's feelings and help him work thru them. Training cannot happen when the horse is focused somewhere else.
The rider should try not to let things get "personal". If at anytime, you find yourself getting angry because things are not going as planned, take a break. Don't take it out on yourself or your horse.
Slow things down. Possibly all conditions for training are not right at the moment. Revise your immediate training plan. Make today's goals a little smaller, more reachable.
A rider can never quit a horse too early, but can quit him too late.
"The rider, when the day's work is completed, is to dismount immediately rather than have the horse carry him back to the stable, be it so much as a mile, for horses greatly appreciate such courtesies." ~~Xenophon
Sometimes going slow is the fastest way to get there.