Failure. We don't like to talk about it. But we all worry about it.

We worry about it in the present: Why am I not doing better in my career? Do my coworkers think I'm messing up? Is my boss unhappy with me?

We worry about it in the past: Why didn't I speak up at that meeting? Is it my fault I got laid off last year? What if I hadn't left that job ten years ago?

And we worry about it in the future: What if I don't get the project done on time? Will I end up without a bonus? Am I going to get fired?

I've recently been talking to CEOs as part of a project I'm working on documenting how people recover from their careers taking unexpected dips. I've met people who've seen their hopes dashed when they were passed over for promotion, others whose vast fortunes were erased by accounting scandals, those who've had their comfortable lives upended when their parents lost their savings, and even people who've simply and terrifyingly slipped and fell, putting them out of work and nearly into paralysis.

In all these stories, the common thread has been that while the failure was, theoretically, avoidable, since the cause always came from an unexpected direction it wasn't really preventable. One man, walking to a doctor's appointment while worrying about overseas competition for his manufacturing business and political intrigue involving investors, was hit by a car. He literally did not see it coming.

I can empathize with these managers. I once mismanaged my own company into ruin. I had an (initially unknown to me) alcoholic business partner and my trust and faith in him brought us both down. In my case, "only" 200 people lost their jobs and I ended deeply in debt. More difficult to cope with, both my business partner and father died during the crash of the company.

At one point I found myself standing on a Manhattan street, totally motionless, my body unwilling to move forward or backward. Wracked with doubt about every decision I'd ever made, I must have stood there for a half hour.

And here's where the CEOs I've talked with are different than me. Faced with failure, they stayed in motion. They quit the bad job, they separated from investors they conflicted with, they got up off the sidewalk and went back to work.

They suffered as much as I did from doubt and worry, but they kept at it. Sometimes they succeeded, sometimes they didn't. As Tom Watson, the founder of IBM said:

Would you like me to give you a formula for success? It's quite simple, really. Double your rate of failure. You are thinking of failure as the enemy of success. But it isn't at all. You can be discouraged by failure — or you can learn from it. So go ahead and make mistakes. Make all you can. Because, remember that's where you will find success.

Here's another way to think about it. Once I was trying to fix a toilet and water began to blast upward from a fitting. The building Super, who was watching me, commented, "You know the difference between a professional plumber and an amateur?"

"No," I said, frantically searching for a towel.

"The professional makes as many mistakes as the amateur," he said, swinging a wrench onto the main valve and closing off the fountain, "The difference is, a professional fixes them faster."

One of the first things I ask my new clients to do is write down three of their key strengths and three of their flaws. Typically, strengths might be attention to detail, focus, and drive; flaws can be delegation, lack of creativity, and people-management skills. I then ask clients to look carefully at what they have written. Often, they will stare at the paper and then at me. They will ask me to explain. Rarely do they see the connection.

The fact is that our flaws are often the mirror image of our strengths, and it's important to realize that we should not over-develop our strengths, causing them to turn into flaws. There is always an optimal point: confidence that doesn't border on arrogance, wit that doesn't slide into sarcasm, and diligence that doesn't become perfectionism. I have observed many leaders who have fallen into the strengths/weaknesses trap. Having been praised and rewarded for demonstrating particular strengths throughout their careers, they become blind to the shadow sides of these strengths. Often, this blind spot can derail a career.

I was therefore very interested to read about some new research that delves into leaders' dark sides. The researchers interviewed 18,000 U.K. leaders over a decade (1999 to 2009) to discover what derailed them under pressure. They identified 11 derailers — strengths which turned into flaws under pressure. These include shrewd-mistrustful; charming-manipulative; vivacious-dramatic; and diligent-perfectionist. These "Dark Side Characteristics" were present in 85 percent of the leaders surveyed, with 16 percent having three dark-side characteristics.

Interestingly, the most common dark side characteristic in the U.K. is dutiful-dependent, that is being too appeasing and accommodating when under pressure. Additionally, a quarter of U.K. leaders also tended to withdraw from difficult situations and become remote.

The implications of these findings are significant for companies battling with the uncertainties of the new economic era. Consider, for example, a company whose senior executive team is uniformly dutiful: what happens when they encounter a crisis or an all-powerful CEO drives their strategy in the wrong direction? Common sense dictates that they should meet the crisis head on or challenge the CEO, yet the research suggests they are more likely to jointly keep their heads down. This behaviour was revealed at the Royal Bank of Scotland as it came under severe pressure last year: it became apparent that the senior team had not properly challenged the strategy or called the CEO to account.

I am sure that we can all come up with examples of managers and leaders who are unaware of the shadow side of their enthusiasm (volatility), charm (manipulativeness) or focus, (passive aggression). All too often they are aware only of the positive effects of their personalities, screening out the negative impact on those surrounding them. If they remain impervious to feedback — or the organizational culture doesn't support individual feedback — then senior leaders can be in serious danger of sabotaging their careers as well as their companies. A leader embarking on a senior role should remember that there are many things beyond his or her control that can derail them: they should not add their own blind spot to that list.

So what can organizations and individuals do?

1. Look out for potential derailers at the recruitment stage. Don't be dazzled by outstanding performance in one area only to overlook a lack of basic competences in other areas. Tough, results-focused executives might be desirable, but these traits must be balanced with some understanding of how to manage people. Similarly, recognize that success in one company does not necessarily mean guaranteed success in another organizational culture.

2. Ensure that careers are managed in a sustainable way. Many organizations fast-track high fliers beyond their real capabilities, ignoring their limitations and flaws until they emerge in times of pressure. This can be highly damaging to the individual, team, and organization.

3. Use feedback and psychometric tests to raise awareness. Regular 360 feedback surveys can help executives and top teams (including the CEO) identify, understand, and analyze the real impact of their flaws. Psychometric tests such as the HDS can also help executives understand where the fault lines lie in their personalities. Using this information, they should work on a personal strategy to manage these flaws, either through coaching or training programmes.

4. Understand how traits vary across generations. The research found, for example, that members of Generation Y are more compliant and dutiful than other generations, which could make them reluctant to take decisions or challenge the status quo. Generation Xers, meanwhile, have more social skills, but can be perceived as being superficial or manipulative if they overplay their hands.

What are your thoughts on the dark side of leaders? Have you any further evidence or experiences of how strengths can turn into weaknesses? Do you have any experiences to share of derailers — your own or those of others? And have you come across any interesting ways to ensure that strengths are not overplayed?