There is something called the “Shadow” in psychology. Carl Jung came up with it.
The shadow is the repressed self.
For example, if you are a creative person and you live in a family where siblings are down to earth, you might have been told to be more “sensible” or “practical” millions of times.
You have repressed your creativity.
As a result, you might loathe anything that is related to art. You might even vigorously call artists “quacks” or their art a “fraud" and "pointless”.
The unhealed wound inside of you, the repressed self, will express itself violently. You might not be aware it’s here, but it influences your life.
I think every author/writer has a shadow and this shadow appears in their work.
There are themes I love juggling with such as prejudice and lies. Both have hurt me deeply. I have even written the story of a very religious girl who pays someone to lie for her because she cannot handle the burden of lying. At the same time, she finds the act of lying rewarding.
I think my shadows are probably in relation with the moral codes that were pounded into my head since very young, but by now I have made my peace with a lot of my shadows. Still, they appear here and there through my characters.
I believe this happens to every writer and it is cathartic to let the shadow out here and then.
And you, are you aware of your shadow and the way it influences your writing?