Inception

Mal: "You're infecting my mind!"
Cobb: "I was trying to save you."
Mal: "You betrayed me, but you can still make amends. You can still keep your promise. We can still be together, right here. In the world we built together."

"What is the most resilient parasite? Bacteria? A virus? An intestinal worm? An idea. Resilient... highly contagious. Once an idea has taken hold of the brain it's almost impossible to eradicate. An idea that is fully formed - fully understood - that sticks; right in there somewhere."

"I knew Inception was possible because I'd done it to my wife."

Cobb: "What do you want?"
Saito: "Inception. Is it possible?"
Arthur: "Of course not."
Saito: "If you can steal an idea, why can't you plant one there instead?"
Arthur: "Okay, this is me, planting an idea in your mind. I say: don't think about elephants. What are you thinking about?"
Saito: "Elephants?"
Arthur: "Right, but it's not your idea. The dreamer can always remember the genesis of the idea. True inspiration is impossible to fake."
Cobb: "No, it's not."

"You mind telling your subconscious to take it easy?"

Cobb: [when he notices that he's being followed] "That price on my head, was that dead or alive?"
Eames: "Not sure. See if he starts shooting."

"These aren't just dreams, these are memories and you said never to use memories!"

"The moment's passed. Whatever I do I can't change this moment. I'm about to call out to them. They run away. If I'm ever going to see their faces I've gotta get back home. The real world."