Have you ever heard the saying, “Fake it till you make it”?

Simply put, it refers to acting a certain way until you actually begin to feel that way. Motivational speakers often explain the power of this life hack to crowds of business or sales professionals.

However, you can use it in your everyday life as well. If you want to feel more confident when you’re at a party or get-together, for example, just act like you are a confident, relaxed person. Walk into the room with your head held high and a walk that says you know what you want out of life.

One of the most important parts of this technique is your facial expression.

Did you know that you can actually trick your mind into thinking you feel a certain way? Normally, we look at things the other way around—whatever emotion we feel or think about (joy, sadness, anger, etc.) is consequently displayed on our face (using our eyes and mouth).

But, the opposite is also true. If we put a big smile on our face, we can’t help but feel better. That’s right, smile really big and see if you don’t feel happier. You can actually change your mood instantly just by changing your facial expression.

That’s what I like to call “Paint Your Face How You Want to Feel,” or PYFHYWTF. If you want to feel joyful, put a big grin on your face. If you want to feel calm and relaxed, smile serenely and narrow your eyes a bit like you’re basking in the breeze on a warm beach and almost ready to doze off.

The effect is even more powerful if you do this while looking in a mirror.

There is an abundance of science behind why smiling makes us feel better. When our smile muscles contract to form a smile, they fire a signal back to the brain to stimulate the production of endorphins, dopamine, and serotonin that make us feel happier.

And when we’re happier, we smile more. It’s a positive reward cycle that can be set into motion just by smiling.

Imagine yourself as being happy and the feelings will follow.

Psychology Today has several online articles about the positive aspects of smiling—here and here are just two of them. The British Council even recommends holding a pencil between our teeth to exercise our smile muscles.

Not that you’d necessarily ever want to feel angry, but if you did, you could make yourself feel that emotion just by creating and angry expression.

That’s why when something small bothers you and you start to show it on your face, the emotions involved can quickly escalate. Before you know it, you’re full of rage over something insignificant.

You have much more power over your emotions than you might have realized.

Go on, give it a try. Stand in front of a mirror and give yourself your best smile and see what happens.