A Quote from Portal 1
GLaDOS
The Enrichment Center is required to remind you that the Weighted Companion Cube cannot talk. In the event that it does talk The Enrichment Centre asks you to ignore its advice.
More quotes from Portal 1
Area and state regulations do not allow the Companion Cube to remain here, alone and companionless.
Time out for a second. That wasn't supposed to happen. Do you see that thing that fell out of me? What is that? It's not the surprise. I've never seen it before! Never mind, it's a mystery I'll solve later... by myself, because you'll be dead.
This is your fault. I'm going to kill you. And all the cake is gone. You don't even care, do you?
Please note that we have added a consequence for failure. Any contact with the chamber floor will result in an unsatisfactory mark on your official testing record, followed by death.
There was even going to be a party for you. A big party that all your friends were invited to. I invited your best friend, the Companion Cube. Of course, he couldn't come because you murdered him. All your other friends couldn't come, either, because you don't have any other friends because of how unlikable you are. It says so right here in your personnel file: "Unlikable. Liked by no one. A bitter, unlikable loner, whose passing shall not be mourned. Shall NOT be mourned." That's exactly what it says. Very formal. Very official. It also says you were adopted, so that's funny, too.