“People who say that yesterday was better than today are ultimately devaluing their own existence.”
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Karl Lagerfeld 57
German fashion designer 1933–2019Related quotes

Book Sometimes you win Sometimes you Learn

“I do not think much of a man who is not wiser today than he was yesterday.”
Included in Portrait-Life of Lincoln (1910) by Francis T Miller
Posthumous attributions

During his interview at Larry King Live, (16 May 2000). Available Transcript at CNN.com: President Nelson Mandela One-on-One http://transcripts.cnn.com/TRANSCRIPTS/0005/16/lkl.00.html
2000s

On Literature, Revolution, Entropy and Other Matters (1923)
Context: A new form is not intelligible to everyone; many find it difficult. Perhaps. The ordinary, the banal is, of course, simpler, more pleasant, more comfortable. Euclid's world is very simple, and Einstein's world is very difficult — but it is no longer possible to return to Euclid. No revolution, no heresy is comfortable or easy. For it is a leap, it is a break in the smooth evolutionary curve, and a break is a wound, a pain. But the wound is necessary: most of mankind suffers from hereditary sleeping sickness, and victims of this sickness (entropy) must not be allowed to sleep, or it will be their final sleep, death.
The same disease often afflicts artists and writers: they sink into satiated slumber in forms once invented and twice perfected. And they lack the strength to wound themselves, to cease loving what they once loved, to leave their old, familiar apartments filled with the scent of laurel leaves and walk away into the open field, to start anew.
Of course, to wound oneself is difficult, even dangerous. But for those who are alive, living today as yesterday and yesterday as today is still more difficult.

“Never look back on something bad, yesterday is gone, today is now, tomorrow doesn't exist.”

“I reserve the right to be smarter today than I was yesterday.”
As quoted in Loggers' Handbook Vol. 36 (1976), p. 72; also in North Western Reporter, Second series (1992) https://books.google.com/books?id=I1KaAAAAIAAJ; similar remarks have been attributed to others, including more recent attributions to Adlai Stevenson and Abraham Lincoln.
Variant:
I insist on being smarter today than I was yesterday.
As quoted in How to Win the Meeting (1979) by Frank Snell, p. 3

“No yesterdays are ever wasted for those who give themselves to today.”
Eric Stanley on CBS News https://www.youtube.com/watch?v=ksYrWGivy5A
2011