Having to take a pet to the vet's office is the worst. It's terrible for almost everyone involved. Your pet is scared and possibly sick as it is, then they get blasted with this sensory overload of new things. They'll see and smell all kinds of other animals, whether they want to or not.
Even getting them to the vet is a hassle. Many animals are excellent at pattern recognition. Like when your dog sees you going towards where you keep the leash and goes nuts, or when your cat hears the can opener and comes running. Much in the same way, pets somehow often seem to know when they're going to the vet. So now you're chasing your pet all around the house trying to get them in the car.
The cockatoo in this video is just like that. His name is Max and he doesn't care for trips to the vet. When Max notices the telltale signs of an impending car ride, he sprints to hide underneath a shelf and then throws a legendary tantrum.
The first half of the video, Max sounds like he's reciting an incantation designed to ward off the cameraman. He vocalizes similar sounds over and over, presumably trying to outlast his owner.
Then, Max comes out from under the shelf and changes his tone completely. Now he sounds like he's really giving the owner a piece of his mind. He stomps his feet and paces back and forth in protest, but to no avail.