Read the biography of any big-wig, and one quality that repeatedly emerges is the extraordinary energy with which they throw themselves into pursuits.

This is how Elon Musk makes simultaneously launching electric cars and actual rocket ships easy. How Ben Franklin retired in his forties, invented the lightning rod, and helped write the Declaration of Independence.

But what drives these fantastic leaders, thinkers, entrepreneurs? Is it their sheer motivation?

The simplest definition of motivation boils down to wanting a change in behavior, thoughts, feelings, self, environment, or relationships.

There’s rational motivation in which we’re motivated by visible opportunities, reaching our goals. We make the best decisions given our information and options. Then there’s biased motivation where we hold a bias toward a decision that conforms to what we already know. We ignore ways to make our lives better.

Often, our motivations (or lack thereof) are a hidden logic we don’t actively perceive. The thing you feel motivated to do is what you feel you’re meant to do. The thing you don’t feel motivated to do is probably for reasons you’d rather not reveal or admit to yourself or can’t seem to figure out.

Perhaps, we are inherently biased because of the infinite number of choices before us seem impossible. Rationality is limited. We can’t fathom the idea that we as individuals have the power to send rockets to space, so we don’t motivate ourselves towards that goal.

If you believe that motivation is rational and an objective indicator of where your pursuits should aim, listen to it. If you feel uninspired, it could be that your current opportunities are inadequate or nonexistent. If you feel invigorated, take it as a sign you’re on the right path.

If you believe motivation is biased, you have to actively and consciously recognize all the available opportunities.

In the short term, your motivation can be up one day and down the next. Starting might be difficult, but stopping even harder. You have frustrations that make you want to throw things but go away after you get into bed. You wake up and are excited to see what the day brings.

Susan Fowler, author of Why Motivating People Doesn’t Work and What Does: The New Science of Leading, Energizing, and Engaging, says that “People want to thrive. People want to flourish, and if they’re not, why? Why aren’t they?”.

Your motivation is an important signal in the long-term. Lulls in your motivation are like red flags in a relationship. One, two, even three red flags you can let slide, but any more and it’s time to be honest with yourself and break up. If you can’t motivate yourself for months or years, the problem is probably with the project. Flip the classic “it’s not you, it’s me” on its head. There are lots of opportunities in this sea; you just have to be rational and recognize them.