Confidence and Strength

Recently, I was participating in an online discussion about Tri training, and how it effects other aspects of one's life.

Here is the question that was posed:

"Which brings me to a idea and I'd love to hear what folks think. I've been reflecting on the importance in triathlons to have the confidence to believe you'll do well by whatever standards you set for yourself. Part of that confidence comes from proper training... that is, if you follow a training plan that has been put together by experts, you can be more confident that you'll "do well" in what you trained for. But there's another piece of that confidence, which has to do with how we face and embrace experiences that are new to us, especially ones that in the past where we might have mental roadblocks. Triathlons might be a physical manifestation of this situation (and a simpler one), but there are lots of others in life. Do any of you see taking on triathlons as "training" for breaking through these roadblocks in other parts of our lives?"

And my response:

I've been thinking about this question since you posted it, Stu. The answer is most definitely yes, for me. This past summer, I was in a terrible working environment. The regional managers of the company had made it very clear that their goal was to eliminate my job. I was faced with daily pressure to justify my position, while continuing to do my job.
Every day, before I walked into the office, I would stop at the door and say to myself, "You just completed a 25 mile bike ride last night, up Krumkill hill. You can handle anything they throw at you."
On a funnier note, whenever the regional manager would come into the office, and give me a hard time, I'd picture his pasty white, overweight, flabby body in a wet suit... It made me laugh every time

Today, I am in a much healthier work environment. But it is still extremely stressful, because I deal with life and death situations every day. Sometimes, when I'm in a stressful, new or difficult situation, I'll close my eyes for a second, picture the toughest hill I've ever rode up, and know I have the strength and patience to handle the issue.
So, yes, Tri training has helped me immensely in life.

And now, my question for each of you:

What do you participate in, that improves your confidence and self esteem? What is it that gives you the knowledge that you are strong and competent, and can push through tough times?