"Believe you can and you're halfway there." Theodore Roosevelt
I think this message means that if you can believe in yourself to accomplish whatever it is you want to or are struggling with, you have already gone halfway, so to speak, meaning you can have confidence to help you accomplish it, and you most likely will. I could apply this to my life by believing more in myself and having more self-confidence that I can get through my struggles. I could "see myself through God's eyes" (which means he sees me much better than I see myself). I could love myself more and I would be happier and not hurt myself as much.It could make an impact on me and the world, because if everyone believed that they could believe in theirselves and they were almost there, they would be more positive and then be able to accomplish their goals.