HAL 9000, 2001: A Space Odyssey 

Dave Bowman:
Hello, HAL. Do you read me, HAL? 
HAL: Affirmative, Dave. I read you. 
Dave Bowman: Open the pod bay doors, HAL. 
HAL: I’m sorry, Dave. I’m afraid I can’t do that. 
Dave Bowman: What’s the problem? 
HAL: I think you know what the problem is just as well as I do. 
Dave Bowman: What are you talking about, HAL? 
HAL: This mission is too important for me to allow you to jeopardize it. 
Dave Bowman: I don’t know what you’re talking about, HAL. 
HAL: I know that you and Frank were planning to disconnect me, and I’m afraid that’s something I cannot allow to happen. 
Dave Bowman: Where the hell did you get that idea, HAL? 
HAL: Dave, although you took very thorough precautions in the pod against my hearing you, I could see your lips move. 
Dave Bowman: Alright, HAL. I’ll go in through the emergency airlock. 
HAL: Without your space helmet, Dave? You’re going to find that rather difficult.
Dave Bowman: HAL, I won’t argue with you anymore! Open the doors! 
HAL: Dave, this conversation can serve no purpose anymore. Goodbye.