Smile. It’s Monday.

It might surprise you to know it there’s no proof to the old saying, “It takes more muscles to frown than it does to smile.” On average a smile uses 12 muscles and a frown 11.

Still, because humans generally smile more than they frown, our smiling muscles are naturally stronger. That makes smiling easier. And you can feel this in your face. It definitely takes more physical effort to frown than to smile.

So, that’s at least one good reason to smile today. But, if you need more, we have them.

Fritz Strack and his colleagues in a 1980s study at the University of Mannheim in Germany revealed even a forced smile boosts humor. They asked some study participants to hold a pencil between their lips and others to hold it between their teeth. Why? If you try this yourself, you’ll notice a pencil between your teeth will tend to force a smile while one between your lips makes you frown.

Both study groups were tasked with reading a series of comics and rating the humor. Those with the pencil between their teeth (the smiling group) consistently found the reading funnier. Smiling does more than tell others you’re feeling good. It also helps you feel a lighter, happier.

Psychologist Ed Deiner takes this a step or two further. Through his research, he finds that the number of times we smile or experience positive thoughts and emotions greatly affects our happiness. Sounds obvious, yet the frequency of these experiences is the real key. What matters less is how intense or how big the feelings are. In other words, someone who racks up a dozen positive experiences in a day will be feeling better than the person who garners just one, regardless of the intensity. So, while moving into that new house or apartment may make you temporarily happy, it’s the little things throughout the day, week, and month that sustains your happiness and keeps you feeling happier longer.

What else can you do to stay happier longer? Besides smiling more? Well, unsurprisingly, it’s the standard basics of good living: eating right, getting regular exercise, meditating and keeping your stress at manageable levels, being social, and doing good things for others. Yes, doing things for others is actually one of the most “selfish” things you can do to keep you happy.

Does this mean living happier is easier than you thought? It’s a pleasant thought that something so important might be relatively simple. And that’s something to smile about… on Monday and every day.