I think it probably helps when you're not only good at what you're doing, but also are super into the project.
My performance is abysmal at my day job because I really can't bring myself to be interested in the subject at hand. And yet I'll regularly work until the wee hours in the morning on personal projects without even realizing what time it is.
My performance is abysmal at my day job because I really can't bring myself to be interested in the subject at hand. And yet I'll regularly work until the wee hours in the morning on personal projects without even realizing what time it is.