James mentioned recently (it could have been Texan99, but I really think it was James) that he sometimes has the disquieting experience of people speaking as if some science fiction concept were science fact.
Had one of those today. Another social worker - these people have graduate degrees, remember - mentioned that one of the common worries about time travel isn't really true. One doesn't change history when one goes back, one goes into a slightly different dimension* (commonly called an SDD, I imagine, in the jargon of the experienced), so your own real time isn't affected at all. He seemed quite serious about this. I replied talking offhandedly about science fiction and the various possibilities that had been written about. I was careful not to bluntly announce that this only happened in fiction, yet repeat the point several times that writers created these ideas. I don't know if it stuck.
*Don't you just hate it when that happens?