I'm not even sure how to answer this one....

Haven't you ever worked on something that had any meaning to you? Haven't you finished a huge project and then sat back and looked at it and felt that feeling of accomplishment, of wow, of...well, whatever you want to call it....

That feeling. That's why.

Haven't you ever had something mean so much to you that you had to be involved in it? Haven't you ever cared so much about something that you couldn't just sit by?

That feeling. That's why.

Have you ever had children, or something you wanted to pass on to them? Haven't you ever held a child in your hands and saw the future in their eyes?

That feeling. That's why.

There's a song here.....

That feeling. That's why.