how to stay motivated in workouts

A friend who is trying to get in shape asked me recently how I motivated myself to get up every morning and work out. And why it is that I like competing in triathlon so much. I think a lot of people wonder this about me, and they think that they could never have the same motivation. But as always, I told my friend that I wasn't an athlete in high school and never thought of myself as someone who could become an athlete. I only started running about 7 years ago, and when I did, it was .1 ...