There have been several interesting threads on how authors tend to put their own characteristics into their characters, but I haven't seen any (recently anyway, if I've simply missed them, feel free to post the link) on a related topic: when people assume something an author writes is about himself or herself.

I'm a little surprised that even fellow writers sometimes seem to have a hard time making a distinction between an authorial "I", a first-person approach, and the actual writer.

I suppose it should be a compliment to the writer that they've made things realistic enough that someone assumes it to be true, but I also think it can be a disservice to the writer, not giving him/her the credit for being able to imagine and create beyond his/her own experience.