I'm a nanny. I've worked with kids between 1 and 15 years old, And right now I'm with a wonderful little 3 1/2 year old boy.
Everyday, I pick up my little boy from preschool, and we go to the park. Today is a cold, crappy kind of a day, I left my book at home and am hungry. As a result, I really didn't want to go sit at the park while he played.
Usually, we go to the park every day - unless I get a report from his teacher telling me he was behaving badly in school. When I hear that, we aren't allowed to go to the park. It obviously makes him cry, whine, promise he's sorry etc, but I think it has helped him think about his actions in school if he knows it means he has no park.
So I picked him up from school today, and of course he asked if we could go play. I was about to say no, when I realized that a 3 year old doesn't understand the difference between us not going because he was badly behaved, and us not going because I'm being lazy. So I changed my answer to yes.
The same logic applies to horses...don't take away their reward because of your personal problems etc. For example, if you are trying to have them have more speed, or endurance or whatever, and don't have much time, don't take away their breaks because you don't have time! Work your horse hard, and increase towards your goal a little. But they are still doing what you ask, and trying their hardest, so you need to recognize that and give them their reward.
Otherwise, they don't understand why they don't get a reward. They think that they did a bad job and it wasn't what you wanted and they are getting punished for it.
Just some food for thought! I find myself giving my horse less breaks etc when we're on a good role, or when they're doing something awesome! But it should be the other way around!