But if we're not focused on making money and being productive, how will capitalism flourish?

To be fair, this is one study that identified one specific factor related to happiness (with their sample). Our emotions, and how they color our experiences, are much more complicated. Simply trying to make this one change in your life may help, but it's certainly not a panacea. (Although a lot of sites like to take single research studies like this and talk about them as though they are...)

That's actually exactly how I've been living my life for the past two years or so. There was a point in my life where something in my head just sort of...clicked. And my whole outlook on life changed to the better. I prioritise nice and happy things in my life while also taking a serious look on not-so-fun things that just have to be done.

And ever since, my life hasn't ever been any better than it is now. I strongly believe it is because of this way of thinking.