I loved reading your comment, @letalis-laetitia! (And I'm very sorry for the long delay! I am going back now to find comments I have missed.) Processing things is a great reason to write fiction, in my humble opinion. But that aside, writing what you know can infuse your writing with an amazing richness because you are pulling it from a place of knowledge and experience.
I have heard famous writers say that every character has pieces of them. And that makes so much sense to me. We humans are such complex beings. To be able to draw from the various aspects of our personalities and our past experiences in the craft of fiction is an amazing gift.