What I know for sure is that it's only when you make the process your goal that the big dream can follow. That doesn't necessarily mean your process will necessarily lead you to wealth or fame. In fact, your dream may have nothing to do with tangible prosperity and everything to do with creating a life filled with joy, one with no regrets and a clear conscience. I've learned that wealth is a tool that gives you choices, but it can't compensate for a life not fully lived and it certainly can't create a sense of peace within you.
I don't know what kind of egomaniac is sitting at home thinking about the impact they have had on the culture. It's not something I actually think about until it comes up.
If something feels right, I do it. If it feels wrong, I don't. It's really very, very simple, but you've got to be willing to take your chances doing stuff that may look crazy to other people - or not doing something that looks right to others but just feels wrong to you.
Learn from every mistake because every experience, encounter, and particularly your mistakes are there to teach you and force you into being more who you are.
One of the things that I encourage for anybody who is interested in their own charity or philanthropy is to start from where you are and what has mattered to you.