A few weeks ago, I had one of those days.

No, not one of those days where you you lie around in pajamas eating nachos and wondering why your big project isn’t getting done, but the other kind.

The kind where you know you’re ON FIRE. The kind where you just keep churning and churning through your to-do list and even when the day should be over you put in a few extra hours because you’re just such SO ON FIRE. And, then, when you finally do close your laptop and turn off the phone you wonder why a New York Times journalist isn’t knocking down your day to ask, “So how did you do it? How did you become the MOST PRODUCTIVE PERSON ON THE PLANET IN ONE DAY?!?”

That day was amazing.

And then the next day, the whole nachos thing happened.

When I pulled myself out of bed with a belly full of cheese, I started wondering about what it is that made that one day so amazing, and then the next day such an overwhelming dud. How did I manage to be so productive, and what’s the lesson on how to be productive in general?

Here are the two key insights I came up with.

By Definition, Insane Productivity Can’t Happen Every Day of the Week 

None of us can fire on all cylinders every day of the week. Or, when we do, we quickly experience burn out, as my new book discusses. As such, truly incredible productivity by definition has to happen infrequently. That way, your body and mind can rest and recuperate well to get ready to do it all again.

Productivity Builds on Productivity

The day I was SO ON FIRE didn’t start out amazing. But there was a moment at which I made a decision to put my head down. Just for a short period of dedicated hard work. And, as happens when you successfully get through a short period of good, solid work, you feel psychologically awesome, and want more. That’s what happened that day. Small wins built on small wins, and by the end of the day I was on such a streak that I wanted to keep going.

Ultimately, what I learned in thinking about why I had such a good day – and then why I had such a bad day – was that I simply can’t have those amazing feats of productive genius every day. But I can have them sometimes. And to make them happen, I have to set myself up for success by building on small, early wins in the morning so I can feel the fire.

What about you? If you’ve ever had an insanely productive day, what did it teach you about how to be more productive in the future?