Twenty years from now you will be more disappointed by 

the things that you didn't do than by the ones you did do. 

So throw off the bowlines. 

Sail away from the safe harbor. 

Catch the trade winds in your sails. Explore. Dream. Discover.

- Mark Twain

The pessimist complains about the wind; 

the optimist expects it to change; 

the realist adjusts the sails.

- William A. Ward