I was recently watching a re-run of the BBC4 TV drama The Road to Coronation Street, more as background noise than up-front entertainment. That's not meant as a knock. As these things go, it tells an interesting tale in engaging fashion. But there's a short sequence nestled in there, one that may well have been based on truth, that the filmmakers have shaped into a magical, life-transforming event, one in which impending defeat is transformed into the first steps of victory.

In this particular film, the moment in question comes when Canadian producer Harry Elton is mournfully watching a recording of the pilot show – itself the culmination of many months of hard work, talent and risk-taking – knowing full well that, thanks to the Granada bigwigs who first greenlighted the show, it will never be screened for the general public. They just won't be interested in something this humdrum, he has been assured by his bosses. He's just in the process of terminating the VT playback when tea-lady Agnes walks in. She becomes instantly hooked. As she sits down in front of the monitor, captivated by the programme and commenting on the action, Elton watches on and a look of inspired realisation crosses his face, emphasised by the length and intimate tightness of the close-up and the transitional notes of the score. As I watched this scene, I stopped what I was doing and faced up to the fact that I when it comes to these inspirational moments, all of my critical faculties fly out of the window. I am, I have realised, a hopeless sucker for them.

If you're still not sure what I mean then allow me to explain. These are very specific moments in particular types of film, usually dramatic stories and often based on fact, whose characters usually work in the sciences or the arts. Imagine if you will a biographical drama about Alexander Fleming, who for those of you who didn't pay attention at school was the scientist whose work, coupled with a fortuitous discovery, gave birth to Penicillin. Picture the scene as it plays out in this as-yet unfilmed biographical drama. After several months of hard work, Fleming takes a much needed family holiday and returns to find his laboratory in its usual untidy state. In the corner sits a stack of staphylococci cultures that he deposited there before he went away. He's just looking them over when he notices that one of them has been contaminated with a fungus that has destroyed all of the immediately surrounding staphylococci colonies. In the film this wouldn't be a casually observed moment, but one shrouded in wonder, a long, wide-eyed stare, an almost mystical note of music, a revelatory close-up and an expression of gradually dawning understanding. Oh, I can see it now.

This is not, I should point out, a universally effective trick. If the film is driving me potty then suddenly inserting an inspirational event is not going to make me go all gooey eyed. I do need to have a degree of emotional investment in the characters and their plight to get that small thrill that such moments seem to incite – it's just not going to work in shouty bollocks like Transformers: Revenge of the Fallen. But given that such turnaround moments have almost passed into cliché, I should by all rights groan when they turn up in films that I'm until then enjoying. I should really be saying, "Oh not this again..." but instead find myself smiling like a small child who has been handed a large and colourful lollypop. I'm guessing that I'd secretly love to believe that life is just like that, that problems can be solved and lives turned around by a single, brilliant flash of magical inspiration, one so perfectly realised that it can be seen and felt by everyone around you. It rarely if ever is, of course. That's part of the joy of film, that it can transform how something actually occured into what how like you'd love to believe it happened.

I've tried to think back on a few of my favourites and have found it surprisingly hard to recall specific examples, so am open to suggestions. But here are a few that have stayed with me over the years and still put a Cheshire Cat smile on my face.

Jim Broadbent as W.S. Gilbert in Mike Leigh's sublime Topsy-Turvy, as he toys with a samurai sword and in a flash knows exactly what shape the next opera he and regular collaborator Arthur Sullivan will take. It's a boldly realised revalation, announced by a gliding dolly shot and Broadbent looking directly into the camera and smiling, as if he's aware of the audience and keen to share the moment with us.

Ed Harris as American abstract expressionist painter Jackson Pollock begins dripping colours on a large canvas on the floor and discovers the unique beauty of action painting. The film, in case you've missed it, is Pollock, and was also Harris's first film as director.

Jeremy Brett as Sherlock Holmes in the Granada production of The Crooked Man sits Buddha-like overnight, pondering on the location of a missing man, then washes his face in slow-motion and claps his hands at his reflection as the penny finally drops. Is followed by a hilarious carriage ride with a grumpy Watson about a Gladstone bag. "It contains the key..."

Five to ten minutes before the end of almost every episode of House M.D. – which is, of course, a modern reworking of Sherlock Holmes – where the titular doctor suddenly realises what's making his patient so ill. These moments became so much part of the show's identity that other characters started commenting on them when they occured, as in "You've just solved the case, haven't you," or "Now you're just going to walk out without saying anything, aren't you."

And best of all...

The glorious climactic moment of revelation in Life Story, Mick Jackson's beautifully realised BBC film about the discovery of the structure of DNA. Jim Watson and Francis Crick, portrayed by a divinely cast Jeff Goldblum and Tim Piggott-Smith, have approached the problem of unravelling the structure of DNA from every possible angle, drawing heavily on the work of others and yet repeatedly failing to make the dots join. Watson is once again trying to put the pieces together when a chance comment from a colleague alerts him to the fact that one of the formulas on which their calculations are based is actually wrong. Based on this new information, Watson cuts out two models, and in what for me (and I'm guessing fellow reviewer Camus as well) remains probably the single most electrifying inspirational moment in cinema (and I'm counting this richly filmic work as cinema, despite the fact that it was made for TV), he places one on top of the other and they perfectly match. Goldblum's look of wonder, the accompanying note of music... oh, its just divine. Now why the hell isn't this film available on DVD?