Anyone that knows me can tell you that my two favorite types of people (other than my wife and my children of course) are kids and and the elderly, for various reasons in each instance. In working with both groups of people in and outside of the dojo, I have learned two main concepts that apply both in and outside the dojo, one from children and one from the elderly.
Key concept learned from children: open-mindedness.
Children tend to be more receptive to new ideas and thoughts than adults, mainly due to their small time spent on Earth, they haven't developed any filters like adults tend to over time. Children aren't afraid to try doing their kata different ways or mixing a little grappling with their taekwondo that will help them become a better martial artist.
Like the "old folks" say, " a closed mouth never gets fed." Neither does a closed mind.
Key concept learned from the elderly: simplicity.
The elderly love and embrace the concept of simplicity, whether it's because (as some elderly say) they're too old to learn new things or (my favorite) because simple works. They could care less about being able to throw a picture-perfect side kick to the head of a 6'8" opponent or the elaborate escape from a choke hold that takes 2 minutes to perform and looks pretty during a demonstration....especially when a kick delivered to the knee and a old-fashioned foot stomp will do the trick.
"Easy does it!"