Mister, if you can get the power on, that train will take us straight to the surface. I would try it myself, but it's a long way down the generator room, and there are... things, in the way...

Scientist: "Do you think we should appeal to the alien authorities?"
Scientist 2: "Absolutely not!"

Please be advised that a noticeable taste of blood is not part of any test protocol but is an unintended side effect of the Aperture Science Material Emancipation Grid, which may, in semi-rare cases, emancipate dental fillings, crowns, tooth enamel, and teeth.

The Enrichment Center reminds you that the Weighted Companion Cube will never threaten to stab you and, in fact, cannot speak.

GLaDOS: "Look, you're wasting your time. And, believe me, you don't have a whole lot left to waste. What's your point, anyway? Survival? Well, then, the last thing you want to do is hurt me. I have your brain scanned and permanently backed-up in case something terrible happens to you, which it's just about to. Don't believe me? Here, I'll put you on:"
Strange voice: Hellooooooooo!
GLaDOS: "That's you! That's how dumb you sound! You've been wrong about every single thing you've ever done, including this thing. You're not smart. You're not a scientist. You're not a doctor. You're not even a full-time employee! Where did your life go so wrong?"

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.

Momentum, a function of mass and velocity, is conserved between portals. In layman's terms, speedy thing goes in, speedy thing comes out.

That thing you burned up isn't important to me; it's the fluid catalytic cracking unit. It makes shoes for orphans... nice job breaking it, hero.

Who are you? What is that? Oh, What's that? What's THAT? What is THAT?

Remember, the Aperture Science Bring Your Daughter to Work Day is the perfect time to have her tested.

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.

Well, you found me. Congratulations. Was it worth it? Because despite your violent behavior, the only thing you've managed to break so far... is my heart. Maybe you could settle for that, and we'll just call it a day. I guess we both know that isn't going to happen.

This is your fault. It didn't have to be like this. I'm not kidding, now! Turn back, or I will kill you! I'm going to kill you, and all the cake is gone! You don't even care, do you? This is your last chance!

Where are we going? Are you coming back? What's that noise? Is that a gun? Do you smell something burning? Ooooohh... what's in heeeere?

While it has been a faithful companion, your Companion Cube cannot accompany you through the rest of the test. If it could talk - and the Enrichment Center takes this opportunity to remind you that it cannot - it would tell you to go on without it, because it would rather die in a fire than become a burden to you.