"The moments matter, but what follows does not." - The Samurai Leader
It's having no fear to do things "right" at this moment, living these moments to the fullest, and not worrying about what bad the future might bring.
Stress is "sugar coating" word for being afraid (acceptance, results, etc.) Stressed out people are definitely not cool. No fear!
Interestingly, being cool is the core zen (buddhist) principle of doing right things now and no clinging to stuff. Even 2600 years ago people knew how to be cool. We could use some coolness in today's over-stressed world.