Ten days ago a hitherto unknown Texan teenager by the name of Cella tapped out a tweet that read: “Ew, I start this f*** a** job tomorrow”, followed by half a dozen thumbs-down symbols.

Someone showed the tweet to the manager of the pizza parlour that had just hired her, who tweeted back: “And . . . no you don’t start that FA job today! I just fired you! Good luck with your no-money, no-job life!”

Judging by the response online most people under 25 see Cella as a hero. She was exercising her right to freedom of speech. She did not mention the name of the restaurant so it was outrageous that she got fired for it.

Most people over 25 took the opposite view. They thought she had behaved like a spoilt brat and deserved what she got.

Yet both sides agree that to get the sack before you even start a job is pretty remarkable. Twitter appears to have changed how we work forever.

On closer inspection, Twitter has changed nothing – all it has done is speed things up a bit, which is a thoroughly good thing.

In the old days the girl would probably have been fired once she started snarling at customers. By ending the agony before it started the company gained, as did Cella’s putative colleagues – as no one likes working with someone so dedicated to moaning that she has begun before she has anything to moan about. Even the girl herself gets something out of it (in addition to her brief celebrity) as she was relieved of a job she had decided to hate.

Rudeness

The only thing wrong with the manager’s tweet was its rudeness. The situation was of his making. He hired the wrong person, and in getting rid of her he should have admitted his mistake and said sorry.

All managers, even experienced ones, often pick hopeless people. That is not surprising given how hard it is to ever know what someone is like until they start.

What is surprising is how long it takes for the axe to fall on the misfits. Managers delay for three powerful reasons: they cling to the fond hope that the person will change (they almost never do); they are reluctant to admit to having made a dud choice; and they shrink from the unpleasantness of having to fire anyone.

Last week I met a big name ex-chief executive who is credited with having hired some of the most successful executives in the UK. He told me he was no better at selection than the next person – out of every five people he chose one turned out great, three okay, and one awful. What he was good at, he boasted, was the speed with which he gave the duds the boot.

His proudest moment was firing a senior executive after just one day in the job. Within hours of the man joining a queue of people had formed outside the chief executive’s office to complain about the newcomer’s abrasive style. By teatime the chief executive took action, told the man he had made a mistake, apologised, paid him some money and off he went. Both sides then pretended it had never happened. In those days there was no Twitter, no news story and no fuss.

When something is wrong it is not just the employer who knows at once. An acquaintance of mine was recently headhunted to a new job on almost twice the money. By the end of the first day he had taken against the people, the atmosphere and the pressure they were under. On the morning of the second day he quit, and by that afternoon he was heading back to his old employer.

I am not saying everyone should leave a new job at the first hitch, nor that all disappointing hires should be fired instantly. Just that when the mismatch is fundamental – which happens more often than you would think – there is no such thing as too quick.

One man I know of was hired to a top job a couple of years ago. He was interviewed by half a dozen senior people, all of whom were impressed by his intelligence, his strategic thinking and his apparent conviviality. Yet he turned out to be a disaster. He was arrogant, and loathed by all the people who reported to him. It took a year to get shot of him, but by then the damage to the business was prodigious.

Had anyone consulted the chief executive’s PA, who escorted him from reception to the interviews, things might have gone differently. When she took him up in the lift he did not meet her eye, and barely responded to her pleasantries. She knew it was never going to work.

Security guards

To ask security guards, receptionists and PAs what they think of candidates makes every bit of sense. If 360 degree appraisals are a good idea, 360 degree interviews are a better one. In the former, fearful underlings shrink from telling the truth; in a 360 interview they would rush forward to prevent the rude, the overbearing and the maladjusted from getting the job in the first place.– Copyright The Financial Times Limited 2015