Denial: Raging against what is.
Resignation: Giving up hope.
Acceptance: Acknowledging the situation, but not giving in to it. That gorilla knows that he's stuck in the cage for now, but he's still thinking of a way to get out. Open the door, and he'll be gone in a flash. Denial gorilla might not even notice the door is open, he's so busy pulling on the bars. Resignation gorilla doesn't think he can do better; open the door, and he'll stay put.