Do Something that Hasn't Been Done Before

“That’s the problem with a lot of people; they don’t try to do stuff that’s never been done before, so they never do anything, but if they try to do it, they find out there’s lots of things they can do that have never been done before.”  
In his "Blog of Impossible Things, Joel Runyon says he got an unexpected ass-kicking in a conversation with an "elderly gentleman" who interrupted his work flow in the coffee shop. Joel says he learned something from the old guy about doing the impossible. Looks to me like there's a lesson there about paying attention to the "old guy" or "old woman" who obviously doesn't know anything.