Three.

Three things in life that, once gone, never come back -

Time

Words

Opportunity

Three things in life that are most valuable -

Love

Self-confidence

Friends

Three things in life that are never certain -

Dreams

Success

Fortune

Three things that make a man/woman -

Hard work

Sincerity

Commitment

Three things in life that can destroy a man/woman -

Alcohol

Pride

Anger

Three things in life that, once lost, hard to build-up -

Respect

Trust

Friendship

I received this list of three's in an email. Think about them...they seem to ring true to me.