If you postpone your happiness, assuming that you will find it in some future achievement, you are setting yourself up for disappointment.
Worthwhile achievements do not come easy.
Failure is always an option.
If you are not happy before failure, you will probably not be happy after failure.
Conversely, you may be successful.
You may accomplish your goals and achieve exactly that which you set out to achieve.
But achievement is not some magic pill that will solve all of your problems.
It may make you feel better for a brief moment, but you bring yourself with you wherever you go.
So who you are before you achieve your goals will be who you are after you achieve your goals.
If anything, achievement amplifies unhappiness.
It shines a spotlight on the fact that happiness is not found through external means.
You must find something more permanent and reliable than achievement to base your happiness on.
Look inside; do not wait.