We interviewed 500 of the most successful people in the world about their passions — from Nelson Mandela and Richard Branson to Steve Jobs and Oprah Winfrey.

There are at least 6 ways they all expressed using to figure out whether they were truly passionate about something or not:

1. The Flow Experience: You lose all track of time…well, then you’re doing something that has triggered a passion. Where did that hour go?!

2. Irritation: It may seem odd to look at something uncomfortable as a window into passion, but it definitely can be. The reason something annoys you is because it violates something that you love, and you can often find a passion on the other side of irritation.  Think about it–there are so many things in the world that could upset you, but you choose very specific things to feel annoyed about. Take a look at your next irritation and see if there’s a rainbow on the other side of it.

3. Fatigue: If you’ll still do it when you’re tired, it’s a passion.

4. Failure: You bounce back from setbacks quickly when they happen to one of your passions. And you’ll probably scrap yourself off the payment and start doing it again despite failure!

5. Free:  I’m not suggesting that you work for free, but when you’re engaged in something you’re passionate about, you don’t need money to motivate you.  You’re probably putting in more effort than you’re charging for and you might even volunteer to do it.

 6. Bore People:  When you ask someone about their passion, they will rant and rave for much more time than is politically correct.  You’re at that cocktail party, and this guy is go on and on about his passion, and your eyes are glazing over…you’re looking at your watch and planning somehow to escape.  Well, that’s passion. You will do it despite the status it gives (or doesn’t give you!)