Since then, my writing has progressed, but my basic sources of inspiration have stayed the same. I have no trouble painting the characters who I associate myself with in a negative light, but it gets tricky when you start to reveal unflattering truths about those who are closest to you. Especially when the best writing typically stems from tumultuous relationships with said close family/friends.
Having experienced this moral dilemma, I can't say there's an obvious right or wrong answer. I once wrote a piece that centered around a very dark period between me and my mother, and quality-wise, it turned out to be some of my best writing. I soon learned that my mother was not comfortable with sharing that piece of her life in the context of my piece. While I was annoyed that I would have to re-write an essay that could affect my grade, I realized that keeping a positive relationship with my mom was worth more than a shiny GPA. In that case, the answer was obvious--I was writing a non-fiction piece, and I'd gotten very explicit lack of consent. Non-fiction is a little more black and white. If you're writing entirely about a real person with real issues, they always have the right to veto that piece. That's not censorship--rather, that's protecting another person.
However, fiction is where interpersonal drama often becomes more ambiguous. My friend brought up an excellent point when he was discussing his own writing project. He mentioned the fact that while his writing is far less autobiographical than my own, he focused on troubled family dynamics (particular parental pressure) because of his own relationship with his mother. He noted that if someone ever wanted to buy his screenplay, he would jump at the chance, but there was still that nagging concern about what his family would think if they read his screenplay or watched the movie. Coming from an exceptionally supportive family, I immediately assumed that his parents would realize that his own happiness and success was the most important, and they'd be proud. However, this isn't always the case. Oftentimes this is why some of the best writers are the most isolated (also, alcoholism. But that's for another time).
I'm normally an advocate for being overly careful not to step on anyone's toes, in the case of fiction writing, I'm still a firm believer in facing hard, unflattering truths. I'm not saying you should go spouting out your best friend's deepest, darkest secrets alongside their name and address, but limiting one's creative outlet in fear of hurting someone's feelings is, in its purest form, censorship. You shouldn't walk up to your father and say "hey look, your emotional unavailability made me unable to form meaningful relationships!" (think how awkward THAT Thanksgiving would be), but on paper, that's free game. Not only is this creative freedom therapeutic, but it's real. More often than not, the reader can tell when you're trying to tip-toe around the core issue, and it makes for a very artificial, very dull story. In most cases, poignant trauma and distress seamlessly translates to poignant fiction.
It's also important to realize that fiction--at least, good fiction writing--very rarely features one-dimensional characters. Just because a certain character seems more troubled than others, that does not mean that she is the clear-cut "villain." Exhibiting flawed, complicated moments just shows that the world is full of flawed, complicated people--which family dynamics often enhance.
The moral of the story is not "I hate my mom," or "life would be so much greater if my great Aunt Tina stopped chugging bottles of wine and calling me fat." Stories that expose troubled family dynamics do more than simply point fingers. They make us realize something about human nature, about growing up, about ourselves.