Some great quotes

I am always in awe of some of the great quotes you might stumble across when idly browsing the internet. How do these, usually famous, people dream up such great examples.
A few are included below:

Don't cry because it's over, smile because it happened. Dr. Seuss

Be yourself; everyone else is already taken. Oscar Wilde

Two things are infinite: the universe and human stupidity; and I'm not sure about the universe Albert Einstein

You only live once, but if you do it right, once is enough. Mae West

I think it would be great to be born on Earth and die on Mars. Just hopefully not at the point of impact. Elon Musk