There are so many reasons to fish that I doubt they could all be listed in one place. I have several reasons myself. This attempts to describe just one of them.
Stepping through a doorway. I'm speaking of an internal doorway of the mind here, not the actual door to my house. My mind is partitioned, as I expect most everyone's is, into different sectors. Each sector is primarily a separate place where I operate the mind's machinery for specific purposes. Such as while at work I'm in a sector that is almost completely only for work. When I'm commuting that's a different sector. At home with my wife is another sector. And so on.
Some of these sectors overlap a little. Some of them are easy to transition from one to another. But some are like locked rooms. There's a door, but it's shut and I have to have a key to get in there. One locked room in particular is what I think of as the Zen room. It's a sector that when I can get into it , it is peaceful, regenerative. I'd say happy but that really isn't the right word to use.
I've found two ways to unlock this door so that I can enter this Zen sector. One is by way of deliberate meditation. I've studied meditation, been trained by experts in it, and have practiced it off an on for years. Mostly off. Meditation requires being physically still, and I find that difficult. I'm not a twitchy guy, but I do tend to fidget quite a bit.
The other way is fishing. I can wade out into the river (I'm talking about the real Brazos here, not a mental river) and attain that same frame of mind, go into the same sector as meditation, yet be physically active. Wading and casting do not interfere with this reflective state of mind, the Zen state of mind. Catching fish doesn't intrude either.
This state of mind is impossible to describe with any accuracy. About all anyone can do with words here is like trying to describe the ocean by only describing the beach.. I think every fisherman has experienced this state of mind though, and probably quite often. Words...well I'll try.
My mind is generally concentrated on and around stress points. You know, all the usual stuff like finding money to pay bills, wondering if my job is secure and what would I do if laid off, deadlines at work, jerks in traffic, health concerns, and on and on. My mind works around those the way a mosquito circles around my head - always wanting to come back to those stressers and chew on them. There's a constant inner-monolouge running in my head and it tends to focus on negative things. Not all the time of course, but a big percentage of the time.
Then there is this other place, where these thoughts do not appear. It's a quiet place. Quiet because that constant inner monolouge shuts down. No little voice in my head keeping pace with the clock, talking to me all day long, chewing on stress bones. Without that voice, thoughts don't seem to form. Instead there is just observation of the outside world. I can see a tree and not have the word "tree" pop into my mind. Not only that but I don't begin to classify it as a deciduous, pecan, southern pecan, native pecan, old/young...Normally that's what I do. But in this place I don't. I observe. I see. I see without putting what I observe into a frame of reference. I just simply see - and hear of course. I hear a bird but I don't hear it and automatically categorize it as a mockingbird.
I can catch a fish in this mental territory without doing much more than maybe laughing out loud. Maybe a bit of joy. In fact the whole experience is close to an experience of joy, but a step or two down overall from that.
Aw I give up. Words really don't do that mental sector justice at all. If I wrote another ten thousand words I'd be no closer than I am now. I'm still describing the damn beach.
So I'll stop rambling...for now...and leave with this thought - Fishing is about a lot more than fishing, it's a doorway.