YOU DON’T know real fear until you’ve stood in front of 30 15-year-old schoolchildren on your first day of teacher training. This happened to me nearly 20 years ago, and I still get flashbacks.

Forget what you may have heard of stand-up comedians dying at the Glasgow Empire, there is no audience more discerning or as viciously dismissive as a group of people who have spent a decade in the school system, honing the dark arts.

Each hour of their lives they are faced with teachers talking at them, and they come to know instinctively who’s good and who isn’t, who’s worth listening to and who isn’t; and like Mexican boxers, they only stop beating you up when the bell rings.

One guy on our course came straight from a successful career in banking (“I really want to put something back, you know?”) who we called Three Faults, a nickname cruelly taken from the sport of showjumping: he would go toward the classroom door only to refuse, like a horse shying away from the big jump, his nerve failing him as the hum of the untended class grew louder.

I still remember watching as he stood outside in the corridor, knowing in that moment there was no way back, as he was ushered away by the regular teacher.

When you watch the very best teachers, you’re struck by their quiet confidence, the willingness to engage, their storytelling ability, the gentle humour and, much overlooked, a complete mastery of, and enthusiasm for, the subject matter in hand. But in lieu of these, a few of us thought it was easier to put up a PowerPoint demonstration.

This was the early days of PowerPoint – it celebrates its 20th anniversary this month – but even then it was clear that it would take over the world. To us it was a prop, something to hide behind and, most importantly, a device that promised to make us look more intelligent than we were.

Rather than winning over the audience with the strength of ideas, or argument, we used Dilbert cartoons and ever more creative transitions from one slide to another.

We found that whole text books could be broken down into bullet points and, even better, these could arrive on screen accompanied by the sound of a car crashing, or a woman screaming. The students willingly copied them down and we noted that if they were writing something they couldn’t throw things at us.

My take on PowerPoint was forged in those early days, and nothing I’ve seen since has altered the view: it is the most misunderstood and abused form of software yet invented. What’s more, it so pervasive – it has 95 per cent of the presentation software market and the company estimates that over 30 million PowerPoint presentations are made each day – that it has changed the language of business and, I’m convinced, altered the image of the commercial sector in the public imagination.

Edward Tufte, a design expert, suggests the software “elevates format over content, betraying an attitude of commercialism that turns everything into a sales pitch”.

Its inventors were two American computer programmers, Robert Gaskin and Dennis Austin, who saw a gap for graphics-based presentations at a time when most venture capitalists were still thinking in terms of text-based DOS computer systems. Bill Gates knew better however, and Microsoft bought Gaskin and Austin’s company for $14 million, the Seattle giant’s first acquisition.

Now, every meeting room, lecture hall and classroom is fitted with a video screen and laptop connection, and every business conference starts with a tie-less man in a bad suit, tinkering nervously with a USB port before stuttering, “I’m just going to run through a few slides”, which is up there with, “and this is from our new album” in the pantheon of phrases you don’t want to hear in a public auditorium.

But it was never meant to be like this, say the monster’s creators. The original software was aimed at the relatively small community of sales people who could use PowerPoint’s ability to create charts and graphs to better get their point across to a client. Then Microsoft bundled PowerPoint into its Office packages and the world was turned into a series of bullet points.

To watch how it should be done, find a YouTube clip of Prof Lawrence Lessig, preferably at the TED conference, demonstrating The Lessig Method of Presentation. Like the very best teachers, Lessig tells stories based on extensive subject knowledge built up over years of hard work.

He knows, like every audience knows, that there’s no short-cut to a great presentation. It’s just that most audiences are not as honest as the one found in the classroom.