There's a fascinating moment towards the end of Flare Path, currently previewing at the Haymarket theatre in the West End. The play's set at an RAF airbase in 1942, and one of the principal characters, Doris, is married to a Polish airman who speaks little English. When his plane is shot down, she finds a letter that he'd left with her for such an eventuality. It's written in French, a language she doesn't speak, so she has to get another character to attempt a translation.
The effect of this scene, as we hear a dead man's words of love, haltingly paraphrased into English by a character who's having his own crisis, is extraordinarily moving (and, in this case, very well acted; from my front-row cheap seat, I could see the real tears shed by Sheridan Smith as Doris). The odd thing is this: we watch the scene for its emotional content, but part of our pleasure is purely technical - we enjoy and appreciate the skill with which the dramatist has set up the scene that allows that emotion to emerge.
This is all rather counter-intuitive - you would have thought that it would be impossible simultaneously to engage with a character and to be aware of that character's creator. In the case of Flare Path, the two things actually complement each other - we're more involved with the scene because of our admiration for the skill with which it's been contrived. This joy in the mechanics, in watching things slide into place, is one of the more surprising features of the well-made play.
Oddly enough, the most prominent examples of this kind of technical pleasure are found in the visceral genres of comedy and horror. (The critic Linda Williams has categorised them with pornography as 'body genres', aiming to produce a physical response in the viewer). A good joke is an act of misdirection, sending the brain down one path, then colliding it with a punchline from another - we laugh because we appreciate what's been done to us. Farce takes this to extremes - the best farces are like great, gleaming machines, with characters and sub-plots working together like so many pistons. It's not a coincidence that one of the first major French farceurs, Alfred Hennequin, originally trained as an engineer.
However, the real home of this kind of reaction, especially in the cinema, is the horror film, and the slasher film in particular. Look online, or in Fangoria, and you'll see detailed, sometimes jaded criticism of the many ways which screenwriters have found to kill people off - I first became aware of this reading a review in Shock Xpress which referred to penis amputation during fellatio as 'that old chestnut!'.
Jigsaw, the villain/hero of the Saw franchise, serves in this respect as a surrogate for both fan and screenwriter - like them, he's constantly trying to think up new, intriguing traps for his victims. As Rattigan sought to contrive the best emotional scene, the horror writer seeks inventive ways of killing - always looking for the well-made slay.