Things are not always what they seem.
A writer's mind is always working. It formulates ideas then takes them to the extreme. After all, what is writing except exploring the possibilities? Sometimes those possibilities and ideas stem from a real life experience taken a step further. A difficulty with your computer at work leads to a story about an artificial intelligence taking over the world. A scary commute leads to a story about a runaway bus. A weird dream about a loved one who has passed away leads to a spooky ghost story.
There are no limits save the limits you put on your imagination. A deeply logical person would immediately denounce the improbable for the more likely outcomes but the writer goes straight to the improbable and builds on it.
Sometimes though truth is stranger than fiction and the writer can get bogged down in describing the truth. Strange truths are sometimes more difficult to sell to the audience than acceptable fiction. Would you want to read a story about real-life parasites invading the human host or suspend your disbelief for the less credible alien larvae hatching out of the chest of an astronaut? Too close to home must be waved off. Give me the outlandish any day.
My challenge as a writer has been and probably will continue to be that my friends and family might read into my writing some literal truth about my personal situation based on one of my exaggerated writings. A story about a rape might ring a little too true and therefore must have come from a personal experience when in fact, it was simply a detailed research effort including interviews with real victims. After all, every book about writing tells you to "write what you know" but most of the time what I know is pretty boring so I like to take my strange ideas to the next level. That requires research and I think I'm pretty good at research.
The writer, therefore, must be careful when they write and if they are a good writer, they can convince the audience that what they write might have just been a real experience. The truth is, it doesn't always have to be.
After all, things are not always what they seem.