The world is a looking-glass, and gives back to every man the reflection of his own face. Frown at it, and it will in turn look sourly upon you; laugh at it and with it, and it is a jolly kind companion.
Fishing provides that connection with the whole living world. It gives you the opportunity of being totally immersed, turning back into yourself in a good way. A form of meditation, some form of communion with levels of yourself that are deeper than the ordinary self.