Be thankful that you don't already have everything you desire.
If you did, what would be there to look and looking forward to?

Be thankful when you don't know something.
For it gives you the opportunity to learn.

Be thankful for the difficult times.
During those times you grow.

Be thankful for your boundaries.
Because they give you opportunities for improvement.

Be thankful for each new challenge.
Because it will build your strength.

Be thankful for your mistakes.
They will teach you valuable lessons.

Be thankful when you're tired and weary.
Because it means you've made a difference.

Pam Fraser

http://www.poemhunter.com/poem/be-thankful/