The Wolf of Wall Street, Jordan Belfort, has the same problem as me: everyone thinks our job is easy and glamorous. For myself, I play along, upping up the wild, enriching aspects because, well, if they’re thinking that already, admitting the ‘truth’ – my opinion – isn’t going to help. They’ll feel betrayed and dirty, as if I’m calling them a moron right to their face.

The film industry is exactly like this. Even though anyone can be in it theoretically (cue the man sweeping up after the circus saying, “What? And quit showbiz?”) because it has a million different jobs to it and the core makers are two layers down from the glamorous patina the rest of us see. Any author waits for the day when they can say breathlessly “…the rights to my book have been bought by a film producer!” Understandable excitement is correct: films are universally wonderful, bigger than life messages that bring powerful ju-ju.

Whatever you do, making a film – even a crappy one – is just about the best thing ever. You can read how hard it is to actually make a film, of course, but few people do. They’d rather mortgage their house to make their dream come true because, seriously, how hard can it be if thousands of people have made films already? I blame the Beatles for that lyric in All You Need Is Love: “There’s nothing you can do that can’t be done.” Swines.

Unless you work in the industry or are nearby, you have no idea what it involves. I am sure you could say the same of the cut-throat world of academia, media moguls or indeed the Big Swinging Dicks of the financial industries. Outside of music and art, there are very few areas where some will struggle forever on the fringe, just to get a little gig here and there. There are very few industries that carry this veneer of glitter that covers the charmers, the slavers, the con artists, the lucky bastards and the truly gifted.

For example, only a few can make films that actually generate a profit for their investors and see off the critics and never all the time. You can’t, as one potential investor said, “just make a slate of successful films.” Of all the algorithms in the world, he had to walk into mine. You can’t make a bunch of Schindler’s Lists and expect to make your financiers happy: even Steven Spielberg has to team up with money from India to make a feature; big stars have trouble getting their own projects financed. Studios and independent producers alike find funding hard to come by – there’s money there, for sure, but getting it – that’s the problem. You need a solid plan to get money. You need a good script. You need connections and you need a good pitch. But most importantly you need both endurance and professionalism. This is not the entertainment industry: this is show business.

Unless you count a glass of prosecco and a vol au vent nourishment, the glamour isn’t something you can eat. Some of the biggest, most alluring franchises being made today at Pinewood Studios, are eyeing their budgets so tightly it feels like they’re making regional TV.

There are good reasons why the traditional means of getting into the film business was by starting as a runner – for your own safety and sanity. The slog is huge. Full weeks of 14-16 hour days are common, with early to work and late to bed pushed to the point where your body and brain are running thin. There’s always pressure. The catastrophes that happen in the Peter O’Toole comedy My Favourite Year only touches upon it: the star runs amok, the head honchos have to deal with a hydra-headed monster of trouble, meanwhile, the young’uns are taking the weight – and things go wrong. So every moment is damage limitation and minimizing fuck-ups. As one designer told me, “You work as hard on a bad film as you do on a good one – sometimes you work harder.”

Some of the best work will never be seen. Beautiful sets – worlds created from a computer through to hammer and nails put in by fat men in dungarees – only last the duration of the production. Concept art that dazzles the eye and stirs the mind. Songs, costumes, makeup and hair designs, concept vehicles, locations, ideas that started and were scrapped, scenes cut from the finished product – there is a whole 7/8ths of another film connected to the 1/8th you see.

So, the real glamour of the film industry is not saying at a party, “Yes, I make films.” The real magic is walking onto a set, standing amid a new world you’ve helped to build or watching the dailies and seeing where it everyone’s work comes together. As one scenic painter said to me, stopping in the midst of laying down what swear-to-God looked like Italian marble swirls (it was just paint), “It’s too late for me to do anything else. But I think I might be getting better at this.” Filmmakers are gypsies, they’re addicts, they love what they do. And man, do they hate it when they’re not working. But, worse, they’d hate to be paid to do anything else. As I said, you’d have to be inside to know that. And yes, I’ll have another vol au vent, thanks.

Karen Krizanovich began her career as Sex Agony Aunt for Sky Magazine and writes for the Sunday Times, GQ and others. When not being admired, she is much sought after. Follow her on Twitter at @Krizanovich