When we go trail riding we always make sure we have plenty of fly spray to mix up. Fly control for horses not only makes their lives more comfortable, but is also more enjoyable when you are riding or working around them.
I never get in a hurry when I am spraying them. This helps them stay calm and relaxed and they won't shy away from you as much.
My horses don't seem to be bothered by being sprayed. They seem to know it helps keep the flies away. There is such a difference when they don't have to always be swishing their tail and stomping their feet.