“The brick walls are there for a reason. The brick walls are not there to keep us out. The brick walls are there to give us a chance to show how badly we want something. Because the brick walls are there to stop the people who don’t want it badly enough. They’re there to stop the other people.”
― Randy Pausch, The Last Lecture

Watch Randy Pausch give the last lecture on video here:

Have no fear of perfection – you’ll never reach it.
― Salvador Dali

Failure is not the deterrent for the next try. Rather, it is information that empowers the next step.
— Craig D. Lounsbrough

Let failure be your workshop. See it for what is is: the world walking you through a tough but necessary semester, free of tuition. 
— Steven Heighton

Realize your worth and trust your ability, so you no longer confuse failure with defeat!
Deon Christie

When you fail is when you need to celebrate.
— Stephen Tobolowsky

Parenting is the privilege of constant failure… and being loved anyway.
Damon Thueson

You can learn a lot from your mistakes when you aren’t busy denying them.
Oscar Auliq-Ice