Every writer gets this question in some form or other unless they keep their identity a secret. People want to know if you model the main characters in your books after yourself, or if you write romance, if the love interest is like your significant other. I think readers mostly assume there must be a high correlation, especially if you’ve done a good job of making the characters feel real.
The first time I was asked a version of this question was by my hairdresser. She’d just read VEILED MIRROR. “How much of you is in Beth?”
I tried using a great answer I’d once heard another author use: “There are elements of me in every character I write.” Apparently that answer works better with an impersonal audience than it does with someone who knows you pretty well. She just gave me the eyeball that demanded a straight answer. My hair was at her mercy so I complied.
Actually, my original answer was pretty close to the truth, as it would be for most writers I know, and readers should be very glad of it. It’s much better to think that some of the great villains of literature were developed from tiny elements of an author’s psyche, rather than being an accurate depiction of a significant part of our personalities. Who wants Hannibal Lector living next door?
As for heroes and heroines, some authors have a fairly consistent type, that makes it seem they’re writing about themselves. However, most writers work hard to make each character distinct and believable. That variety gives us the chance to explore situations we’d never want to be in, and do things we’d never do in real life. Sometimes the exploration is wish fulfillment. More often it’s just the author trying to craft a compelling and entertaining story.
So what did I tell my hairdresser? Pieces of Beth are me. As are pieces of Ellie. But mostly I created them for that story. OTOH, since DANGEROUS TALENTS started out as an experiment, Celia is probably more like me at the time the book was written than any of my other heroines are.
My heroes? Well, half of them are inspired by my husband. And the other half I just made up. 🙂
Frankie's Soapbox 
I tease my husband and tell him that my heroes are based on how I wish he would behave (all the good parts of course). In response, I get a manly sigh and an eye roll.
LOL! One quirk my husband has that I haven’t put into any of my characters yet, is that my husband has a mind that collects all sorts of interesting info. He can be extremely helpful with research–of many subjects. 😉
I give a similar answer to Frankie’s example when asked this question. But since I’m writing erotic, I tend to keep things as vague as possible. 🙂 There are some details of my own experiences in my stories, but that’s not the norm. Most of my fiction is inspired first by an emotional reaction or thought to something I hear/see (music/movie/game/ad/article) which leads to the thought of an intriguing emotional situation or to a series of data results I research in response. This in turn leads to characters, and finally, to a plot that makes a good story.
A lot of authors have mentioned using other media as jumping off points for their creative processes. Other times it’s a little more concrete. You’ve mentioned developing the idea for your excellent story, “From Dover to Victoria Station” (which appears in the anthology GOING DOWN) on an actual train trip in England. We should all be so inspired!
Thanks for mentioning the story! I had a lot of fun writing it (despite that my emotional driver for writing it at the time was my upset around the soon-to-end relationship I was in at the time). The good news? Emotion can be channeled, and even negative emotions can end up helping to create a saleable and hot story. 🙂