Memento Mori (or Carpe Diem) is the anecdote of monks spending their entire days making sand art, drawing it with all intent and perfection just to see nature wash it away and they would restart that the next day. It’s a practice that grounds them and reminds us of the fleeting nature of life… That no matter what you do; your aspiration, your dreams, whether you succeed or not, whether you leave the world a better place or a worse… It all ends (heck, humanity, even, will end!).
If you push it really far, nothing really matters which is kind of depressing when you think about it…. but at the same time, it’s relieving to know that nothing matters because you can take life less seriously and actually have the freedom to decide what matters to you.
It's also the freedom to decide what your values are and how you want to live your life.