Shiny Happy People....
Facinating article on the physical response of a "negative environment".
Creating Passionate Users: Angry/negative people can be bad for your brain
A key call out in the article quotes Richard Restak
If you want to accomplish something that demands determination and endurance, try to surround yourself with people possessing these qualities. And try to limit the time you spend with people given to pessimism and expressions of futility. Unfortunately, negative emotions exert a more powerful effect in social situations than positive ones, thanks to the phenomena of emotional contagion."
If there ever was a statement that could be directly applicable to Ironman, this is it...