Relying on your own ideas
ה' ידע מחשבות אדם כי המה הבל
Hashem knows that the thoughts of man are futile. (Tehillim 94:11)
You will find that solely relying on your own ideas and efforts to attain your goals will ultimately be a recipe for frustration. If my children only learn one thing from me, I hope they learn that everything I attained in life of lasting value came about only because I davened long and hard for it.