I think "Memento mori" puts everything into perspective.
We compare so much of ourselves and what we have, or haven't got, with others, with our past, with others past.
It's never an apples to apples comparison, and yet we agonise over whether we should do a thing or not, based on - again - other people.
And that perspective can change depending on your daily brain chemistry, you may be up one day and it's a great idea go ahead, and then down the next, and it's a waste of time, futile effort.
But one thing remains the same, we only have this life - the one that's in your hands - and this time today, to do what we will with it, because tomorrow is never promised, what do you have to lose but what you have in front of you - the now.
"Remember that you die"