Sometimes, a story may be rather too baldly revealing of the mental state the writer is in when he conceives it.
I was desperately unhappy in my studies during my first year or two at college (in fact, I continued to be very unhappy with them throughout my undergraduate career; but after the second year, I really ceased to pay them any attention, and amused myself with numerous other activities); and I thought very seriously about quitting - about walking out on Oxford University. I couldn't quite find the courage to do that. So instead I achieved some catharsis by sketching out a screenplay about a student who 'escapes' his dreary life to have a bizarre adventure.
The opening idea - not quite the first scene in the film, but the first idea that came to me in developing the plot - was a montage depicting the steady deterioration of the protagonist's engagement with his studies (accompanied by some appropriately gloomy music; I had the Albinoni Adagio in mind): a repeated travelling shot down the centre aisle of the college library, offering glimpses of various students diligently - or not so diligently - working in each of the booths (my own college library was notorious for retaining medieval bench seats that were only a few inches wide, and thus hellishly uncomfortable to sit on [wider cushion seats were added to these after my first year, but I had endured many hours of excruciating bum torture on those benches]); protagonist always in the last booth, at first working eagerly with heaps of books on the desk around him; then losing focus, nodding off; then visibly struggling to make his way through just one book; then he is reading more eagerly and easily again, but we see that he is concealing a comic book or a pulp novel inside the dry academic textbook; finally, he has brought a pint of beer into the library with him (something that, although officially discouraged, was easy to do and relatively common during my early days as an undergraduate; the library was nearby the college beer cellar, and was unsupervised outside of office hours, but open round the clock).
I came to focus on the idea of breaking out of ruts, of people seeking to transform stereotypical roles into which they had been cast; and the protagonist's college tutor seemed to be the ideal object for this. I liked the idea that although he seemed to be an unsympathetic figure, he had more in common with his disaffected student than was apparent. I decided to avail myself of the identical twin trope - the identical twin with radically different personality. The tutor is visited one night by the twin he hasn't seen for years, and who most of his friends and colleagues don't even know exists. The twin has been an adventurer and carouser, a globetrotter, an explorer (I pictured him in a safari jacket and pith helmet, as an easy shorthand to establish this; though this wouldn't have been very plausible attire in the depths of an Oxford winter). The twin dies, in a drunken fall or somesuch, and the tutor, who is every bit as desperately bored with his life as his student, and who has always envied his brother's more exotic lifestyle, decides to swap identities with him and run away to start a new life.
Cue plot device to create challenge for the protagonist: he has gone to visit his tutor at home on that night, to ask for permission to drop out of college for a year (something I actually did, a little later on), and discovering the dead body - apparently his tutor's body - he falls under suspicion of murder. He now has to hunt down his tutor (I forget the mechanism now, but he discovered some clue to the existence of the twin; I think he may have seen the tutor - or someone who looked uncannily like him - out on the streets of Oxford somewhere), not only to discuss his academic future, but to prove his innocence.
I can't recall now exactly how it was all supposed to fit together; I only wrote some sketches for it, not a full treatment.
Two other ideas I was keen to use, though, were love-at-first-sight and an unexpectedly abrupt ending.
I fancied having my hero being determined to leave Oxford, being at the station about to get on a train, when he sees a girl arriving on the opposite platform who he finds so stunning that he impulsively decides to follow her. (Oddly enough, I did once enjoy a fortuitous romantic encounter - seeing an ex-girlfriend of whom I was still very fond - in very similar circumstances at Reading station a few years later.) Despite this stalker-ish opening, romance blossoms, and the girl is the one person who can help him through his various tribulations. I think this might have been in an early version of the story, before I'd hit upon murder investigation/identity swap plot device, but I wanted to keep it - everybody loves a love story.
I also have a weakness for downbeat, not to say tragic endings. So, I had the idea that my hero - having cleared his name, found love with a beautiful girl, and perhaps even rediscovered his zest for his studies - is knocked down by a bus, just as he's finished a conversation with his girlfriend. This has been lightly foreshadowed by him once or twice early in the story joking that one "might get knocked down by a bus tomorrow" in a 'Life's too short!' argument for behaving more adventurously. (I had a particular paranoia about the buses on Cornmarket, a pedestrian shopping street in the centre of Oxford, where the buses - as the only motorised traffic allowed there - could take you rather by surprise, and often did drive quite fast, quite aggressively through the crowds of people. I strongly suspected that a moment's lapse of concentration on this street might be how I would meet my death.)