I was in the Marines for 4 years. While I was in, I achieved "Guide" in bootcamp (like platoon leader, except you have no power and you suffer the wraith of the Drill Instructors if anyone else screwed up). I was Guide for nearly the entire last half of bootcamp. If you graduate as Guide, you get a promotion and all kinds of accolades for being the best of the best. I was || <- this close.
What does any of that have to do with horses.... The circumstances are different, but the underlying concept is the same. Success is in the details. You can ride every day, take lessons from the greatest trainer ever alive, buy all the best tack and attire, but if you lose your focus (especially as you get closer to your goal), then all that hard work and sacrifice is for nothing. The closer you get to your goal, the more crucial it is to pay attention to your surroundings and keep yourself focused on the task at hand.
I'm only saying this because I need a reminder about this sometimes. With barn drama, work stresses, financial issues, and other boarders wanting to talk when I need to ride.... It's too easy to get distracted. And there is nothing worse, after losing something you wanted, then to look back and think "I should've done [xxx]".
On a side note... I find it highly ironic that I was 'fired' as Guide for not following a directional change, and have yet to ride a dressage test without going off course (with a caller). Guess I'm consistent. ;)