I would never make a moral judgment on an opossum.
I've had more encounters than I would care to count with possums of all sizes that have managed to get into the house (by various and sometimes mysterious means) and have to be caught (by the tail) and ejected when they go strolling casually across the room, paying little attention to any people in the room. They are never as calm as the one in the video, though.
http://i313.photobucket.com/albums/l.../nature/p1.jpg