I had an interesting reaction to rereading Connie Willis' novelette Fire Watch (from the anthology of the same name) last night. The story is part of her universe in which scientists go back in time to experience crucial times in history; in this story, it's the London Blitz and the attempt by the Nazis to destroy St. Paul's Cathedral.
In the story, the narrator has a highly emotional reaction to his experiences, not only because of what he goes through in helping to prevent the Cathedral from being destroyed by fire during World War II, but because he knows that, in 2007, St. Paul's was indeed destroyed by a bomb set by radical Communists.
It's a problem with science fiction written about the near future — especially good science fiction such as this one, which will be read by people in a time after the story takes place. (The story was written in 1983.) At the time, the narrator was living in our future, and so he knew about events that were yet to happen in reality. Yet that no longer holds — his present is no longer our possible future, but a past that takes place in some alternative universe.
Usually, I can ignore that — after all, I have no trouble reading stories in which the early 21st Century is completely different from the reality of it. I can even find it amusing ("Where the heck is my hovercar?") or bittersweet ("Why didn't our 2001 look like this?").
However, in the case of Fire Watch, my reaction was different — and surprised even myself. When the protagonist talks about the terrorist bombs that destroyed Denver and St. Paul's, I wanted to yell at him, "No, no, you've got it wrong! It wasn't Denver, it was the Twin Towers in New York City! And it wasn't St. Paul's, it was the London Metro system! And it wasn't Communists!"
For some reason, I really wanted him to get it right — even though it would have changed the entire point of the story.