In my experience, you do your best work when you’re in a good mood and you’re focused. You can also look at it as being a state of “Flow,” which is a term the psychologist Mihaly Csikszentmihalyi coined in a book with the same title. It’s one of the best tools for productivity.

It’s that state of mind where you’re completely immersed in the task at hand and you lose track of time. You simply feel a deep sense of focus and satisfaction at being productive. As Csikszentmihalyi said in his book:

“The best moments in our lives, are not the passive, receptive, relaxing times—although such experiences can also be enjoyable, if we have worked hard to attain them. The best moments usually occur when a person’s body or mind is stretched to its limits in a voluntary effort to accomplish something difficult and worthwhile.”