I'm surprised that nobody has mentioned flow here. Google it up and read up about it; if you have time for a book, "Flow: The Psychology of Optimal Experience"

I'm surprised that nobody has mentioned flow here. Google it up and read up about it; if you have time for a book, "Flow: The Psychology of Optimal Experience" by Csikszentmihalyi is a great book. This is commonly called "being in the zone." And you reach it when the challenge at hand is slightly above, but attainable, relative to your ability, such that it requires effortful focus to achieve. If you tackle a problem of this sort, chances are you will focus automatically, lose track of time, feel unstoppable, etc. Obviously not all problems are at the appropriate level. There are some people (not myself, unfortunately) who skillfully reshape these problems into smaller tasks, or add challenges, such that they can lead to flow. This skill (of reshaping problems) takes training itself, but I can see it being tremendously useful. Of course, stuff that stresses discipline is probably better than any pill, in the long run. :-)