Inception's mind-boggling ending, as explained by director Christopher Nolan.

Your stomach is clenched the whole time. You feel motion sickness as the bus moves through the city. You grip onto hotel walls as gravity is lost. Your breath catches when you watch Marion Cotillard jump from the window.

The 2010 movie Inception gets to you. Then it stays with you, years after the fact.

The Christopher Nolan-directed film takes you on a journey that renders logic, perception and the division between dreams and reality — absolute mush.

You watch the characters enter deeper and deeper into the dreams of their mission’s target – the heir to an energy conglomerate. They go through layers of his subconscious in order to plant an idea: They want the conglomerate broken into pieces and they want the decision to come from this man.

You pass through multiple layers of unreality. You see Leonardo DiCaprio’s character Cobb fight to get his family back (the mission is doubly important for him). You see him play desperately with a spinning top – a token that helps him distinguish between dreaming and reality.

If the top falls after spinning, he’s back in reality. If it keeps spinning, he’s still dreaming. Sometimes, like with most dreams, it can be difficult to tell the difference.

Then the movie ends. And you groan.

Because the ending leaves you hanging. It leaves you somewhere in between fantasy and reality and you're not quite sure which dimension you've landed in.

It leaves you here: The mission is over and finally, Cobb is with his children. They're in a sunny kitchen with a wooden dining table. The kids are laughing but he's still uncertain. So he spins the top.

It spins. For an extraordinary amount of time. Then it wobbles slightly. Wobbles some more. Keeps spinning.

Then the screen goes blank.

YOU DON'T KNOW IF HE'S ACTUALLY WITH HIS FAMILY IN REAL LIFE, OR IF HE'S STILL DREAMING.

After 148 excruciating minutes, you want to know. You really want to know.

The movie's director Christopher Nolan has since addressed this ending. He did so during a speech he made to a graduating Princeton University class last year.

First off, he spoke about the concept.

"In the great tradition of these speeches, generally someone says something along the lines of 'Chase your dreams,' but I don’t want to tell you that because I don’t believe that. I want you to chase your reality.

"I feel that over time, we started to view reality as the poor cousin to our dreams, in a sense… I want to make the case to you that our dreams, our virtual realities, these abstractions that we enjoy and surround ourselves with - they are subsets of reality."

According to The Hollywood Reporter, he went onto link this to the end of the movie.

"The way the end of that film worked, Leonardo DiCaprio’s character Cobb — he was off with his kids, he was in his own subjective reality. He didn’t really care anymore, and that makes a statement: perhaps, all levels of reality are valid. The camera moves over the spinning top just before it appears to be wobbling, it was cut to black.

"I skip out of the back of the theatre before people catch me, and there’s a very, very strong reaction from the audience: usually a bit of a groan. The point is, objectively, it matters to the audience in absolute terms: even though when I’m watching, it’s fiction, a sort of virtual reality. But the question of whether that’s a  dream or whether it’s real is the question I’ve been asked most about any of the films I’ve made. It matters to people because that’s the point about reality. Reality matters."

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If you, like me, aren't clapping your hands or saying "of course" (i.e.you're not feeling much the wiser), maybe you'll have more appreciation for the beginning of Nolan's speech.

"The most important thing about Bruce Wayne — yes, he attended Princeton, but he didn't graduate," he told the crowd. "So as of tomorrow, you are all already better than Batman!"

Now, that — that is something I can work with.