The past is dead. We can never change it. The future is not promised to anybody. All we ever have is this moment. So, imagine a life where we live each moment like it's our last, like children do. Think of all the joy we could experience!
Start showing up to every moment of every single day fully present and engaged in what you're doing or who you're with. Stop thinking about how things "have to be" because of something happening later. Be here now for this moment and have the most amazing experience you can.
Even when we have what we want, we still can't land in this moment. We cling to the illusion that there are indeed a set of circumstances that, once we achieve them, will finally, miraculously make this moment inhabitable.