I was in a book shop in town the other day and enjoyed listening in on an elderly gentlemen explain his theory of yesterday, today and tomorrow.
He was clearly a man of science and maths.
I’m paraphrasing but it went something along these lines..

“Well, the way I see it is that yesterday is a memory. It’s out of reach. Gone. Tomorrow is merely a dream or a concept. Technically and mathematically there’s no such thing as tomorrow. So why not just live for today and make today the best day you could possibly make it because soon enough it’ll be a memory.”

Words to live by.