These basic things should have been part of your horse's foundation training. Sometimes these basic tasks are skipped over. Sometimes they come back to bite you in the butt later on. What would happen if your horse got loose and he was not used to coming to you, or even being caught. Let's take a look at this.
Horses are sensitive, very sensitive.
They can feel a fly land on their hair. Keep this in mind when working with your horse. If one carefully watches the scenario, you will notice that the owner is standing in the horse's line of vision so that he cannot usually see the tool and is slightly startled by contact with his skin. Additionally, you might watch the placement of your body so that the horse can see your arm and the tool moving towards his back. Verbalizing your actions to the horse can also give him comfort as well as picturing in your mind your actions ahead of time.