Of course, we do sometimes shed tears here, but the odd thing is, especially the older we get, we start crying not when things are horrible, one toughens up a little,

but when there's suddenly, and unexpectedly, precisely the opposite, when they're unusually sweet, tender, joyful, innocent, or kind.

And the little one is Beatrice.

Ah, Beatrice! She's got a mischievous glint in her eye, hasn't she?

Yeah, unbelievable.

Got napkins.

Okay, 33 seconds.

For example, when a rather gruff, distant father shows vulnerability: "I'm proud of you, Flint. I'm amazed that someone as ordinary as me could be the father of someone as extraordinary as you."

When two lovers who'd been rowing make it up.

When a child says something incredibly sweet and innocent.

I'm really good.

When someone is so tender with somebody else.

Far more than grimness, it's a particular grace and loveliness which can, for a moment, feel heartbreaking.

We're crying, not because something sad has happened on the screen, but because what's so lovely on screen is nudging us to realize, semi-consciously, that some pretty sad things have been happening in our lives.

The loveliness is drawing our attention to some of the struggles we face and to some of the things we really want but are finding it so hard to get: reconciliation, forgiveness, tenderness, an end to the fighting, a chance to say sorry.

We start to cry at a brief vision of a state of grace from which we're exiled most of the time.

We ache for all the lost innocence of the world.

Loveliness and goodness can make the actual ugliness of our existence all the more vivid.

That's also why, if we were to consider the unusual project of creating a robot that could cry at the movies, we would have to do something apparently rather cruel.

We would have to ensure that this robot knew all about suffering, for it's only against a background of pain, that beautiful scenes in films become deeply moving, rather than merely nice.

Our tears are telling us something key: that our lives are tougher than they used to be when we were little, and that our longing for uncomplicated niceness and goodness is correspondingly all the more intense.

But when Johnny lifts her at the end...

No, I know, it's very moving.

If you tell anyone, I'll kill you.