Great question and one I don't really have an answer for but I do know that life really does seem a lot better when you are in your favourite fishing spot sneaking up on a large trout.
I find I can spend hours doing the same thing when it is to do with fishing but it is a struggle to concentrate on other things for a much shorter time.
There is something magical about sneaking along the edge of a quiet stream, sun shining and the sound of the water and birds giving a feeling of everything being right with the world.
Then you see a shape... At first you freeze and look more closely, the shape of a large brown trout begins to materialise before your eyes. You watch and plan what you are going to do.
Carefully you strip off some line and gently cast your fly upstream of the fish... Now the heart stopping wait, in reality only a matter of a couple of seconds but it feels like an eternity. You see the fly getting closer and then the magic begins the fish starts to move forward and up toward your fly.
You watch as he closes the gap between him and the fly... His mouth opens as he breaks the surface and your fly is sucked in to his mouth. You wait until the fish turns back down and with a trembling hand you raise the rod tip.
You feel the glorious weight as your line tightens and you make contact with the fish who responds to the sudden pull by using every ounce of his energy and every trick he can muster to escape your grip.
Maybe its the challenge, maybe its simply getting away from the dreary aspects of life for a while... All I know is that I just feel better.
I am by no means an expert although I do have some measure of success and like any good addiction everytime you get a hit you just want some more.
My preference is definately for fly fishing but I am not against spin fishing if the conditions are good and sometimes I have had some good results floating an un-weighted worm through runs in our local river.
As we all know the worst days fishing is still better than the best day at work.