Inception2010

Cobb:
They say we only use a fraction of our brain's true potential. That's when we're awake. When we're asleep, our mind can do almost anything.

Ariadne:
Such as?

Cobb:
Well, imagine you're designing a building. You consciously create each aspect. But sometimes it feels like it's almost "creating itself", if you know what I mean.

Ariadne:
Yeah, like I'm discovering it.

Cobb:
Genuine inspiration, right? Now, in a dream, our mind continuously does this. We create and perceive our world simultaneously, and our mind does this so well that we don't even know it's happening. That allows us to get right in the middle of that process.

Ariadne:
How?

Cobb:
By taking over the creative part. Now this is where I need you. You create the world of the dream. We bring the subject into that dream, and they fill it with their subconscious.

Ariadne:
How could I ever acquire enough detail to make them think it's reality?

Cobb:
Well, dreams, they feel real while we're in them, right? It's only when we wake up that we realize something was actually strange.