I shared a house with a demented Cockatoo once. He was rescued from poor conditions and didn't really know how to be a bird.
They are really smart -- like toddler smart, and very curious. They can solve puzzles, pick locks, and have epic screaming tantrums when they don't get what they want. Every. single. day.
The video below is not mine, but resembles my experience living with a crazy parrot: