The greatest single cause of ...

The greatest single cause of a poor self-image is the absence of unconditional love.
The greatest single cause of a poor self-image is the absence of unconditional love.

Quotes from the same author

Your attitude, not your aptitude, will determine your altitude.
You are the only person on earth who can use your ability.
Remember that failure is an event, not a person.
Positive thinking will let you do everything better than negative thinking will.
What you get by achieving your goals is not as important as what you become by achieving your goals.