Thomas Edison, asked how he felt about over 4,000 filaments tried in unsuccessful experiments to perfect the lightbulb, said, “they were not failures. They were substances that I now know would not work.”

Ronald Knox, wit, priest, detective-story writer and translator of the Bible, wrote:
There was a young man who said, “God
Must think it exceedingly odd
If he finds that this tree
Continues to be
When there’s no one about in the Quad.”

The anonymous answer came:
“Dear Sir, Your astonishment’s odd:
I am always about in the Quad,
And that’s why the tree
Will continue to be,
Since observed by Yours faithfully, God.”