But upon her return, ashen-faced staff greeted her with the news that the woman had taken an overdose. She was released from hospital only to head back to work to plead for her job back. "I spent three hours talking to her," says Joanna. "It was traumatic because she was threatening to kill herself again." In fact, Joanna was left wondering why management had left her in total charge of such a crisis.
In truth, of course, junior managers are unlikely to be left as much in the lurch as Joanna. But inevitably, young high-flying managers will encounter employees who are resentful, spiteful or downright difficult. Reveal weakness and people will exploit it, says Debra Allcock, head of campaigning at the Industrial Society. And at work, she adds, there's nowhere to hide. "It's not like university. If you don't like someone, you can't just ignore it. You have to work with them and face the problem."
In a climate where discrimination cases are rife, this is a particularly common concern for inexperienced graduate recruits. "They can get awfully emotional and blame themselves," warns Ms Allcock. "Or they take sides, and that can be lethal." She speaks from experience - her early career reads like a "how not to do it" management manual. Promoted to lead a team she once worked among, she admits she drove them to distraction with her naturally bossy and demanding manner. The more she harangued them, the less they performed. Eventually they ganged up and protested, which led to an unseemly slagging match. "I was powerless. Discipline had been my only answer and it didn't work." She left work in tears and returned to eat humble pie, eventually rebuilding a relationship with apologies, honesty and a plea for help.
Throwing your weight around is a commonly abused ploy by inexperienced managers, agrees the occupational psychologist Gary Cooper - and one of the worst. "Don't ever try to use your position of authority in a conflict situation," he advises. Managers are equally likely to swing too far the other way, however, ignoring problems or trying to combat them by being "over nice". "I hate to say it, but it's a trap women tend to fall into," says Ms Allcock. "We've been brought up to avoid conflict and we want to be popular. It's much harder to be tough."
Most prevalent is failing to confront obvious problems such as lateness, absenteeism and lack of motivation. The result? The pressure piles up on already overstretched managers to the extent that they virtually end up doing an extra job. With the benefit of hindsight, Emma - a graduate recruit with a leading firm of accountants and self-confessed "Mother Teresa"-style manager - would certainly have been tougher on a slack member of her team. His constant absence in the office (she later learnt he had been sleeping in the loos) led her to exhaust herself completing his tasks while trying to coax him back to the desk.
"I tried to reason and plead with him. I even brought in chocolates and cakes. I went over the top trying to motivate him." But she had neither the time nor the experience to tackle the root cause of his problem - his disaffection with accountancy. "I should have asked advice and been more direct with him. I was just being too nice, trying to protect him."
If you sense a problem, tackle it instantly with a one-to-one interview, advises Ms Allcock. "Concentrate on facts, take the personal out of it." Remember there is no clear right or wrong, just different opinions of an event. Also, avoid harping on about what should have been done - "There's nothing more irritating." A management cliche perhaps, but listening without prejudice to the employee's version of events is key. Inevitably, you'll discover the cause of the problem, be it hassles at home, depression, or difficulties with children.
"You've got to find a way of engaging them in the process, so you're not just laying down the law," adds Professor Cooper. Have enough confidence and diplomacy to show that they may know more than you do about the job. "Assume the worst," he says. "Assume they feel threatened or resent you, and then show you need their advice, their experience."
It's a policy that has got 25-year-old Asda trainee Justin Cowley out of a tricky spot or two. As deputy store manager in Manchester's Moss Side, his aim is to avoid using disciplinary procedures at all costs. Indeed, he's only once had to fire someone caught stealing as part of company regulations, and not without a great deal of personal pain and support from senior managers.
"I try to combat anger by keeping calm. It's very hard for people to continue being angry when someone is being polite - it's frustrating for them but it calms people down. The worst thing is to get wound up - then they can push you further." Remember, he says, you have somebody's livelihood in your hands, so pay them due respect and focus your efforts. Nip a problem in the bud - often through something as simple as changing someone's shifts or giving them leave - and you'll save yourself time in the longer run.
If all else fails, however, you may have to turn to formal disciplinary proceedings - one verbal and two written warnings. Of course, they're best avoided, stresses Ms Allcock, but remember that "they're not a way of punishing, they're a way of cutting out personality clashes and favouritism and helping people keep their jobs". Refer to the company's written standards; agree on targets - as simple as avoiding lateness, for instance - and review them at set intervals. "Your job is to create an environment where people can perform. You want to be someone people can confide in but you have to accept that there are people at work who just don't want to do what they are doing, and if they can get away with something, they will."