The opening to "The Stepfather" is a good thriller opening because the film starts off by showing the audience a man who is doing normal thing, just waking up in the morning and shaving, basically getting himself ready for the day. We don't really expect anything bad to happen from what we are first shown, we do however question why this man may be shaving all of a sudden, he seems to have quiet a lot of facial hair which has taken a while to be grown and now he wants to change his appearance.
As the opening gets further down the line we start to see things that have been left out as though people have left in some ort of hurry e.g. a bowl full of cereal that is on the table, christmas decorations that have been left all over the place etc. The audience still dont assume anything id wrong because when we see these decorations we assume that it just a festive time and people are in a rush to do things. Then finally the background music changes and it we sense something bad ay happen, then suddenly we see a body lying on the floor and the man walks past the body as if its nothing. As he walks out of the house there are more bodies which shows that he went on some sort of killing spree.
I believe that this is a good thriller opening because its interesting and there isn't a dull moment in it which pulls the audience in wanting them to want to know more about what exactly is going to happen and then creates suspense.