opportunity

When one door closes another opens. But often we look so long so regretfully upon the closed door that we fail to see the one that has opened for us.
Helen Keller

Opportunities are usually disguised as hard work, so most people don't recognize them.
Ann Landers

Luck is when opportunity knocks, and you answer. Anonymous

The pessimist sees difficulty in every opportunity. The optimist sees the opportunity in every difficulty. Winston Churchill