Aside from what it teaches you there is simply the indescribable degree of peace that can be achieved on a sailing vessel at sea. I guess a combination of hard work and the seemingly infinite expanse of the sea - the profound solitude - that does it for me.
I'm from Canada and New Zealand feels like you took all the best bits of Canada and squished them onto a tiny island like Hawaii. I was absolutely blown away by the beauty of the South Island.