Crossing Over

I am reading Moon Shot, a pretty good collection of science fiction mystery stories and it got me thinking about crossing genres.  It's one of those things that sounds like a good idea - commercially.  "Hey, if we write a story with elves and cowboys we'll get both the western fans and the fantasy fans!"
For those of you who remember Venn diagrams... you start with this:

 And you hope that your audience will look like this:

But most of the time the audience that shows up looks more like this:

Which is a small group.  The common wisdom is that mystery fans are reluctant to read science fiction -- more so than vice versa.  Like most common wisdom, that may be true, or false, or maybe it used to be true.

I do know that some authors manage to cross borders successfully.  Like mysteries about sports.






Or mystery-westerns.

                                                          Or mysteries set in a fantasy world.

Or yes, mystery-science fiction.

How about you?  How do you feel about reading books that skip across the genre lines?