Your thoughts reshape your brain, and thus are changing a physical construct of reality.
The bottom line is this:
The universe is chaotic, from unpreventable superstorms of wind and rain, to unpredictable car accidents or to the capricious whims of our peers whose personal truths even have the ability to emotionally damage or physically hurt others. And every moment holds the potential to bring you any one of these things, any shade along the gradient of spirit-soaring bliss and soul-crushing grief.
But regardless of what it brings your way, your choice is simple: Love or Fear. And yes, I understand it’s hard to find happiness on those nights when you feel like you’re all alone in the world, when a loved one passes, when you fail that test or get fired from that job; But when these moments come, you do not have to live in regret of them, you don’t have to give them constant negative attention and allow them to reshape your brain to the point that you become a bitter, jaded, cynical old curmudgeon that no longer notices that the very fact that they’re alive means they get to play blissfully in this cosmic playground where you get the godlike power of choice.
What you can do is say; “Yes, this sucks. But what’s the lesson? What can I take away from this to make me a better person? How can I take strength from this and use it to bring me closer to happiness in my next moment?” You see, a failed relationship or a bad day doesn’t have to be a pinion to your wings, it can be an updraft that showcases to you what things you like and don’t like, it can show you the red flags so that you can avoid them. If there was a personality your ex-partner had that drove you insane, then you now have the gift of knowing you don’t want to waste your time with another partner who acts the same way.
If you are mindful to the lessons of the failures, there is no reason that you can’t make the default of every day better than the one before it. Do something new everyday, learn its lesson, choose love over fear, and make every day better than the last. The more you do this, the more you will see and appreciate the beauty of this existence, and the happier you’ll be.