When you're struggling with a task and unsure if you can even make it, what inspires you to keep going?

I have a few things I’m working on that I’ve never had to do before and I have moments of (mild) panic and loss of faith in my abilities. Recently, while watching The Theory of Everything, it occurred to me that if Stephen Hawking could achieve the amazing things he has with the challenges he’s faced, then I must be able to achieve my much smaller goals.

Similarly, I just read this blog post which discussed the diary John Steinbeck kept while he was writing The Grapes of Wrath and how he wrangled with his lack of confidence and self-belief. He overcame his self-doubt to produce a fantastic book.

Things like this help me to push through and keep going. What things help to inspire you and keep you tracking towards your goals?