"If you win, do not boast of your victory; if you lose, do not be discouraged. When it is safe, do not be careless; when it is dangerous, do not fear – simply continue down the path ahead" (Jigoro Kano)
"An expert is a person who has made all the mistakes that can be made in a very narrow field" (Niels Bohr)
"A mathematical theory is not to be considered complete until you have made it so clear that you can explain it to the first man whom you meet on the street" (David Hilbert)
“Don't fear failure. — Not failure, but low aim, is the crime. In great attempts it is glorious even to fail” (Bruce Lee).
"Without frustration you will not discover that you might be able to do something on your own. We grow through conflict" (Bruce Lee).
"Fighting not good, but if must fight... win" (Mr Miyagi, The Karate Kid)
"There are no desperate situations, there are only desperate people" (Heinz Guderian).
"A man's moral worth is established only at the point where he is ready to give up his life in defense of his convictions" (Henning von Tresckow).
"It is not our differences that divide us. It is our inability to recognize, accept, and celebrate those differences" (Audre Lorde)
“you can take the future even if you fail” (ABBA, I have a dream).
"To be a scientist is to be naive. We are so focused on our search for truth, we fail to consider how few actually want us to find it. But it is always there, whether we see it or not, whether we choose to or not. The truth doesn't care about our needs or wants. It doesn't care about our governments, our ideologies, our religions. It will lie in wait for all time..." (Valery Legasov, in Chernobyl, HBO).
"Hey, if you are a scientist and believes in your results, then fight for them; fight for the truth. Listen to others, but fight for what you believe in" (Dan Shechtman, 2011 Nobel Prize Chemistry, https://www.youtube.com/watch?v=EZRTzOMHQ4s ).
"Oh my friend we're older but no wiser. For in our hearts the dreams are still the same" (Mary Hopkin, Those were the days)
or "Oh my friend he's older but no wiser. For in his minds the games are still the same" (my wife's version, for me)