Conjure up the term “bad boss” and what comes to mind? Scenes of red-faced people berating subordinates in public. Smarmy souls taking credit for other people’s work or saying one thing and doing another. Cutting remarks. Yelling. Feel free to continue — we’re sure you can.

This is iconic bad boss behavior — defining in our minds the very essence of what bad bosses do. When we see these things portrayed on TV or in the movies, we can’t help laughing, even while we’re thinking “Whew! I don’t do those things; I’m not a bad boss.”

But, not so fast. Our research suggests that the offensive actions so often associated with being a bad boss make up less than 20% of the behavior that actually defines the worst bosses.

When we analyzed the behavior of 30,000 managers, as seen through the eyes of some 300,000 of their peers, direct reports, and bosses on 360-degree evaluations, we found that the sins of the bad boss are far more often those of omission, not commission. That is, bad bosses are defined not so much by any appalling things they do as by certain critical things they don’t do.

We came to this conclusion from two directions: First in this group of 30,000, we focused on the 11,000 leaders who received the lowest aggregate scores on their 360 feedback reports — the bottom 1% and the bottom 10% — to see if we could spot any early warning signals that might have predicted their lack of success. Then we analyzed a group of executives who had recently been terminated, similarly combing through the data looking for any clues that would explain why they had failed. By combining conclusions from these two groups, we were able to identify 10 fatal flaws that contribute to a leader’s failure— none of which appears in the feedback of the effective leaders.

Here’s the list in order, from the most to the least fatal:

Failure to inspire, owing to a lack of energy and enthusiasm. Again and again failed leaders were described by their colleagues as unenthusiastic and passive. This was in fact the most noticeable of all their failings. Acceptance of mediocre performance in place of excellent results. The poorest leaders did not set stretch goals, inadvertently encouraging mediocre performance by letting people coast along doing less work, less well than their counterparts working for better managers. A lack of clear vision and direction. Poor leaders have a murky view of the future, don’t know precisely what direction to take, and are (not surprisingly) unwilling to communicate about the future, leaving their subordinates with no clear path forward. An inability to collaborate and be a team player. Poor leaders avoid their peers, act independently, and fail to develop positive relations with colleagues. The worst of them view work as a competition and their colleagues as opponents. Failure to walk the talk. Saying one thing and doing another is the fastest way to lose the trust of all your colleagues. The worst offenders here also pose a wider threat as dangerous role models — creating the risk that their organizations will degenerate if others behave as they do. Failure to improve and learn from mistakes. Arrogance and complacency combine in the poorest leaders as they rise, causing them to come to the dangerous conclusion that they’ve reached a stage in their careers where development is no longer required. Closely connected to this failing is an inability to learn from mistakes, leaving these unfortunates to repeat the same ones over and over. An inability to lead change or innovate owing to a resistance to new ideas. Whether stemming from a lack of imagination or simply too closed a mind-set, this flaw manifests itself as a failure to take suggestions from subordinates or peers. A failure to develop others. Leaders who were not concerned about helping their direct reports develop and were not seen as coaches or mentors were highly likely to fail. Primarily focused on themselves, they were not concerned about the longer-term success of their employees or their department. Inept interpersonal skills. These are the leaders who are rude, talk down, yell, and belittle either out of positive malice or out of boorish insensitivity. But even these failings often are manifested in things these poor leaders don’t do. Included in this group are the people who don’t listen, don’t ask good questions, don’t reach out to others, and don’t praise or otherwise reinforce good behavior and success. Displays of bad judgment that leads to poor decisions. Here at the bottom are the leaders who lead the troops over the cliff by deciding to do the wrong things.

While any one of these flaws can be fatal enough to tank a leader, our research shows they are commonly displayed in groups of three or four, as one problem creates another. But the point here is that fully eight out of ten of these flaws stem from things leaders don’t do, and even some of the most obvious bad behavior is often perceived by colleagues, bosses, and subordinates as failures to act more than as obvious mistakes. This makes these flaws difficult to see — they’re not the kinds of flaws we instantly recognize, either in others or in ourselves. And they’re not the kinds of things people call out, since there’s nothing explicit that draws attention.

Worse, they’re the sorts of failing people observe only after weeks and months of working together, which means if you’re one of those unfortunate few heading toward disaster, you could be traveling down this road right now with no hint that anything’s amiss. No hint, that is, unless you take the time to consider not just what kind of a leader you are, but what kind you’re not.