I was a strange child.
But seriously, I always thought Monkey Shines was better than most gave it credit for. It tapped into some primal fears of mine, I guess. I hate having to be taken care of when I'm sick, and in the film when he gets turned on by the creature that was helping him live somewhat of a normal life- it's terrifying.
The reasoning behind the monkey flipping out was a little silly, though. But it's not nearly the worst movie that Romero's made (that title still belongs to Bruiser).