Here’s a tip that can fascinate your readers or audience by setting them up to believe one thing, only to provide additional information that had been withheld and changes their loyalties once revealed.
This technique can be seen very clearly in a Twilight Zone episode entitled, Invaders, in which Agnes Moorhead plays a lady alone on a farm besieged by aliens from another world. The aliens in question are only six inches tall, wear odd space suits and attack the simple country woman with space age weapons. Nearly defeated, she finally musters the strength to overcome the little demons, and smashes their miniature flying saucer. On its side we see the American Flag, the letters U.S.A. and hear the last broadcast of the landing team saying they have been slaughtered by a giant. Structure-wise, nothing changed, but our sympathies sure did, which was the purpose of the piece.
While this example was a message reversal at a story-wide scale, you can easily apply the technique to individual scenes, to a conversation, or even to a single moment. For instance, imagine looking up to see a woman yanking a child by the arm in a very rough fashion. Child abuse, you think, until you see the car coming around the corner that would have hit him if she hadn’t pulled him out of the way. Structure is the same (the child was treated roughly) but the reason turns out to be different than expected, shifting our sympathies once again.