The handful I've had to handle seemed very shy. For most, I'd be going to clean the juveniles' cages, but after they saw me coming to pick them up, they'd usually climb the wall and I would just leave them there while I cleaned up and gave them food.
I had one run on me and be pretty feisty. It didn't bite, but it did not want to be touched one bit.
We had a momma opossum have a surprise litter and since she was already in an outside pen, she got to raise the family there. They were all extremely pleasant and everyone loved them. Momma was a picky eater, but that was about it.