Quite a few of my parables begin life when I notice something about myself that I don't like very much.
Then I sit and speculate, "What is that like?"
For example, let's say you notice that you tend to snap at people when you're tired. You try to come up with some image that could symbolize that. Let's say you come up with the image of a mousetrap. You've set mousetraps all around yourself, a sort of circular defensive wall of mousetraps with you in the middle. Anybody who comes close will step on a trap and get their toes pinched.
So then I'd write a little piece of fiction where that literally happens, or is the literal opening premise. Bellatrix or some other character has set a ring of mousetraps round herself. Maybe the phone rings and she reflexively goes to pick it up and steps on one of her own mousetraps... or whatever.
I wrote a story called "Tumpangisme" whose germ of an idea was an aspect of me that I'm not fond of. Vol.1 Brooklyn has been kind enough to publish the story recently as one of their Sunday Stories. You can read it here.
What was the trait of mine that I based the story on? I'm not going to tell you. Do you really think I'm going to badmouth myself all over the internet?
Anybody who wants dirt on me can go dig it up themself. Maybe start with the above story.