I guess I just wanted to show you that there's two sides to every victory. Those who live to revel in it, and those who died making it happen.

Optimism is a most hopeless feeling, but I must retain it.

You want some weapon schematics? I can show you some fucking weapon schematics! You want a superheated Saturnite Power Fist? I can hook the shit up!

We're made up of thousands of parts with thousands of functions all working in tandem to keep us alive. Yet if only one part of our imperfect machine fails, life fails. It makes one realize how fragile... how flawed we are...

Cave Johnson: Greetings, friend. I'm Cave Johnson, CEO of Aperture Science. You might know us as a vital participant in the 1968 senate hearings on missing astronauts. And you've most likely used one of the many products we invented - but that other people have somehow managed to steal from us. Black Mesa can eat my bankrupt-...

Caroline: Sir, the testing?

Cave Johnson: Right. Now, you might be asking yourself, "Cave, just how difficult are these tests? What was in that phonebook of a contract I signed? Am I in danger?" Let me answer those questions with a question. Who wants to make sixty dollars? Cash. You can also feel free to relax for up to twenty minutes in the waiting room, which is a damn sight more comfortable than the park benches most of you were sleeping on when we found you. So! Welcome to Aperture. You're here because we want the best, and you're it. Nope. Couldn't keep a straight face.