What quotes have inspired you to lead a better life or improve your outlook on life and work?

Whilst watching the movie "American Beauty" last night, I heard a quotation that I thought made a lot of sense when working in sales: "In order to be successful - one must project an image of success at all times" I thought it was a really valid point, as when I am dealt with having to make a decision in a sales transaction, it always makes me feel more confident in a purchase when the salesperson is confident, well dressed and appears successful. It is something that I want to project more in my day to day interactions. I'd love to hear any other inspirational quotations/movie references etc. that have made you lead a better life. Thanks!