There is an American/British children's book called "The Story of the Little Red Engine", or as I remember it, the little red engine who could. Her tag line was to the sound of the steam engine chug chug chug:
"I think I can... I think I can... I think I can..."
Yes! I think I can! I remember my English teacher in high school who also thought this should be my motto. Long ago, he was impressed by my ability to stick to a task (layout and editing of the school's literary magazine) and made a play on my last name. I think I can! complete it and do a good job. I think I can do it!
It's a motto that exemplifies perseverance and persistence. The little red engine had to save the day by carrying the cargo that the bigger train locomotive could not do that day (broken, angry or what ever I don't remember the exact story, am looking for the links on Google as we 'speak).
But no one believed in her at first. She was too small, she never did it before, and well even though she was an engine and built for traveling over mountains, her colleagues (yes, other anthropomorphized trains) said don't do it or discouraged her in some way. But she persevered and succeeded in her task. She could!! She did!! She knew she could, and that made all the difference.