I found for myself – and I've heard many others say the same – that you will be the happiest when you create things.
It doesn't matter what it is that you're creating; it can be music, art, writing, a video, a new concept, an idea, a thing, ANY thing – the act of creating is something magical. It's something that connects you to the universe. It's what you're here for.
And never stop creating them.
And you'll be very, very happy.