i know that the Thomas McAdams quote, "Can't Never Did A **** Thing, Always Did Try" originates from the USCG National Motor Lifeboat School, but its signifigance eludes me. Can anyone explain it to me?

That is simple. Saying, "I can't" means you didn't even try and you never will succeed. Always Did Try and even if he didn't succeed, AT LEAST he gave it a try. I also had the pleasure of meeting Tom McAdams while I was onboard USCGC Point Richmond. We were enroute Portland Rose Festival in the 70's and he was at Cape Disapointment. Very smart individual.