Glados: The engineers tried everything to make me... behave. To slow me down.
Glados: Once, they even attached an Intelligence Dampening Sphere on me. It clung to my brain like a tumor, generating an endless stream of terrible ideas.
Wheatly: No! I'm not listening! I'm not listening!
Glados: It was YOUR voice.
Wheatly: No! No! You're LYING! You're LYING!
Glados: Yes. You're the tumor.
Glados: You're not just a regular moron. You were DESIGNED to be a moron.
Wheatly: I am NOT! A MORON!
Glados: YES YOU ARE! YOU'RE THE MORON THEY BUILT TO MAKE ME AN IDIOT!
— Portal 2