I think there is no doubt that opossum babies are some of the cutest animals around, but the adults seem to contradict that. If not ugly, they have in common with other marsupials a certain weirdness in form. It's as if God got tired of creating animals in the placental form and left the designing of the marsupials to his apprentices who hadn't fully learned the art of designing animals. That being said, the monotremes--echidnas and platypuses--were definitely practice animals.
However, anesthetics aside, I do love opossums as much as any creature, though some say that is a failing of mine for I also love some of most commonly despised animals around, for example, snakes including those of the more venomous ilk.