Chi Wen Tzu always thought three times before taking action. Twice would have been quite enough.

Learning without thought is labor lost.

Learning without thought is labor lost; and thought without learning is perilous.

When it is obvious that the goals cannot be reached, don't adjust the goals, adjust the action steps.

If a man take no thought about what is distant, he will find sorrow near at hand.

Learning without thought is labor lost; thought without learning is perilous.