Beware of missing chances; otherwise it may be altogether too late some day.
I'm aware of what's missing from my life.
Someone who thinks the world is always cheating him is right. He is missing that wonderful feeling of trust in someone or something.
The Bermuda Triangle got tired of warm weather. It moved to Alaska. Now Santa Claus is missing.
Wise sayings often fall on barren ground, but a kind word is never thrown away.