Yes. I was probably in the third grade when I created a space hero named James Shultz who was on some kind of mission against an evil galactic empire. He had to fly his spaceship through the enemy defenses, land on the "bad guy" station, and plant a bomb. He was good with his laser pistol and managed to get to the reactor core and set the bomb. If I recall, he had to fight his way back out and steal a bad guy fighter to get away, which he did just as the bomb went off.

An idea will occur to me - it could be anything - and I try to think of a twist on that idea. After that I fill in a couple of characters, who they are and what they want, then WHY they want what they want. I'll work out some scenes before and after that, then fill in the blanks.
Sometimes these ideas are main plots and sometimes secondaries. Sometimes they start as one and become the other. I'll wind the ideas around each other to see if they work together. If so, I'll start writing scenes. Then I'll flesh out some more and probably start over.

Well, I have two that get lots of use.
The one at work is the most interesting. I've got a giant Millennium Falcon and a zen garden on one side and a bunch of toy dragons on the other. I leave just enough space for whatever documents I need to read and to have access to my calculator. There are scraps of paper all over the place with doodles of fictitious places and snippets of dialog. It's a mess, but my boss lets it go because he appreciates the giant spaceship.
My home desk, where I write, is nothing more than one of those laptop stands on my bed. There is a side pocket where I stick a notebook full of notes and ideas for future stories.

I was an Air Force brat and grew up all over the place. We lived in North Carolina, New York, Texas, and New Hampshire. We never lived anywhere for very long. As a result, I always imagined where we would move next. It was also difficult to have close friends because if it wasn't me moving away, it was probably them.
My characters are not tied to any one place. My heroes have the same affliction. They're always ready to go someplace else if that's what it takes.
The same is true of their relationships. Each will have one, maybe two, close friends to whom they are fiercely loyal, but at their center they are still loners. Often, this is the basis for subplots as one tries to balance friendships over opportunities.

Lady Scarlet came from a trip to the Lego Store. There is a station where you can create your own mini figures (legs, torso, hair, etc.). I made a set of three and was fumbling around in my head as I did about who they were and how they interacted.
Eventually I decided that the female character was the dominant one, dragging the two male characters on wild steampunk-style adventures. After a while a plot began to form and the characters became real. Once I started writing, they were like old friends.
I have lots of ideas for further schemes involving those three Lego people.

I like the control an indie author has over his own career. New technology lets an author decide how and where to market a book.
A big publisher isn't interested in sticking with a small-time writer if a book doesn't immediately take off. Once the initial surge (or lack there of) is over, most books just vanish. I like having the chance to re-launch and re-promote a story at any time. It can give a story many chances to reach its audience.
No publishing company will ever care about my writing career as much as I do.