My favourite inspirational saying is:
Yesterday is history
Tomorrow is a mystery
Today is a gift
That is why we call it the present.
It's clever and it's important. And it rhymes too (well, parts of it!)
I'd like to be able to credit it to credit it to someone but apparently the origin is unclear. People to whom it has been ascribed (Alice Morse Earle, Eleanor Roosevelt, Joan Rivers, Babatunde Olatunji, Bil Keane, Elvis Stojko) are probably just quoting earlier sources.
There is speculation that the last line was added later. That seems like a possibility. The last line only works in English obviously!
It has become so well know that it made an appearance in Kung Fu Panda:
But even though it has appeared in a cartoon, I still think has something important to say.