I think the quote by President Roosevelt, "Believe you can and you're halfway there," is saying that in order to get somewhere you have to believe in yourself and know that you can make it. I think that it also means that believing in yourself takes you halfway and if you don't believe you go nowhere. I could apply it to my own life because a lot of times I doubt myself and don't really believe in myself which is really getting me nowhere. It could change your attitude because you would be more optimistic and have a more positive out look on everything. It could impact the world because we would get more done and not as many people would be sitting at the couch because they are too afraid to do anything.