I started my professional career as an intern at NASA headquarters. My internship boss led IT services for the Science Mission Directorate. Our clients were Program Executives for science missions, like Spirit and Opportunity, Earth-facing missions like LANDSAT, and other neat stuff.

There was no job description for interns, so I decided my job was to be helpful to program execs. I knocked on doors and asked, "Do you need any help with your technology today?" When they said "yes." I was motivated to do whatever I could to make their days better, so they could focus on putting new satellites on unexplored planets.
Mid-summer, NASA HQ launched a project to replace Eudora and Meetingmaker with Outlook. The transition was going horribly. My customers were beyond frustrated; they were executives who had built extremely efficient personal productivity systems. This new project was severely disrupting their work.
I told my boss, "This is terrible. We can't do this to them! I can fix it!" To his credit, instead of laughing me out of his office, Larry said, "How?" I said we just needed to optimize the rollout sequence and the program execs would experience much less grief.
He gave me two developers and three weeks. We designed a ticket and workflow system that managed the flow of the rollout and reduced disruptions. It worked. The applet (built on ColdFusion!) reduced tension, the project rolled out on schedule, my customers were less angry and disrupted, and I felt fantastic.
After that project, I was completely hooked on solving problems with software for big important missions. Thus began my career as a mission-driven consultant. It was my first taste at inspiring action, innovating a solution, and making an immediate impact. It was also my first opportunity to be a solution architect. (It was not my first success at process efficiency; that has been part of my life since birth.)
At the end of the Summer, I stayed on. I worked on NASA problems and deployed solutions for the next eight-ish years.
~Shannon, the Optimistic Optimizer