Don't make your wife watch something scary immediately after she wakes up.
This was a mistake I didn't make. My wife and I are watching Buffy the Vampire Slayer together because neither of us watch it when we were growing up. And not that Buffy is terribly frightening, but when my wife woke up I guessed correctly that she would not want to watch buffy first thing in the morning.
We wound up watching buffy after breakfast and had a good laugh at a mildly creepy episode but it never would have happened had i been rash and asked her to watch it earlier.