What are your goals? Do you work on them every day? I am an excellent goal setter, I am not always good about following through with the daily grind though. Goals can seem so far away and often it seems like, after working day after day, you are no closer to obtaining the goal and it becomes easy to quit.
Alas, that is when you want to work harder, (at least according to the highly successful people). It isn't the challenge that is overwhelming, it is the tediousness and the grind that de-rails goal achievement. It is, even though it sucks, working on it every single day.
I have started using a planner and have begun blocking out slots that I do nothing else but work on my goals. I have also begun to rely on alarms to "remind" me that it is time to work, not play.
So far, it is working, inch by inch.