"You don't fail only if you aren't doing anything".
This is not exactly motivational but helps me a lot with the anxiety caused by other's expectations and disapproval (for example, online criticism):
"What other people think of you is none of your business"
I am someone who struggles with other's opinions as well and caring about them, I REALLY like that last one!
I don't even know where I picked it up but it was almost life-saving :)