As a leadership coach and business consultant, I spend a lot of time thinking about people's mistakes. And over the years I've learned that even the smartest people have errors in judgment, blind spots, and habits that get them into trouble.

Here are some of the dumbest mistakes that the smartest leaders seem to be prey to:

1.     Indecision. One of the worst things that can happen to any team or organization is an indecisive boss. A leader who moves their group in new directions based on new feedback at the drop of a hat, and never seems sure of the appropriate direction, will make employees crazy and never accomplish anything of substance.

2.     Hiding behind closed doors. Whether they're hiding something, afraid of confrontation, or just shy, leaders who stay behind a closed door miss countless opportunities to engage, connect with, inspire and be inspired by their team.

3.     Breaking promises. People take what other people say as their word. If the boss don't keep their promises, it creates a lack of trust that endures for many long years.

4.     Making assumptions. People in power, especially, can do significant damage when they convince themselves they have a grasp of a situation and set out to make assumptions without a reality check.

5.     Taking credit for the work of others. To take credit for anyone else's work is egregiously wrong, but for a leader to take credit from their team members borders on unforgiveable.

6.     Thinking they know it all. The worst thing a boss can do is stop being inquisitive and turn into someone whose response to everything is "I know...." The most valuable words to a leader are "I don't know; I'll find out."

7.     Fudging rules. Bosses who like lots of rules better be ready to enforce them consistently and hold themselves to the same standard.

8.     Poor scheduling. Leaders who hold a team meetings on Friday afternoons an hour before everyone is supposed to leave and speak for two hours will never get a "world's best boss" coffee mug.

9.     Gossip. Gossip should never be tolerated, let alone participating in it, especially when it comes from the boss..

10.  Bad communication. When as the boss you neglect to communicate important information or you leave out important details, you are jeopardizing those who work for you. 

11.  Thoughtless assignments. Some leaders make assignments seemingly at random, wasting highly skilled senior people on everyday tasks and handing the keys to high-stakes complex undertakings to unproven rookies without guidance or supervision.

12.  Being secretive. A secretive boss is ultimately communicating a lack of trust, and their behavior sets the tone for the entire team or organization.

13.  Bad timing. When leaders wait until the last minute to delegate time-sensitive projects, everybody looks bad.

14.  Distraction are disruptive. Multitasking is always poor form when you're engaged with other people. A boss who's messing around on a screen means a team member isn't being heard.

15.  Visible carelessness. One common example: The boss gets a report to review and demonstrates with their comments that they missed critical details.

16.  Clinging to dead wood... Implausible as it seems, I've heard from leaders who received resignations from their weakest team members and went on to persuade them to stay.

17.   ... while not guarding the treasure. The other side of the same coin: People let top performers go without even making an effort to keep them on board.

18.  Promoting problems. Promoting a problem employee, even in hopes that they'll eventually transfer to a different area, doesn't solve the problem and calls the leader's judgment into question.

19.  Visible bias. Bosses who are racist, sexist, or biased against other groups may learn to cover up their words, but their policies and personnel decisions still call them out.

20.  Opposition to professional growth. Poor leaders don't consider learning and development to be important.

21.  Constant complaints. Unrelenting negativity is always bad, but it's even worse when it's coming from the top.

22.  Lack of feedback. Bosses who don't provide appropriate feedback have no right to expect team members to improve.

23.  Showing up impaired. The old-fashioned "three-martini lunch" is supposed to be a thing of the past, but it's surprising how many leaders still imagine themselves to be above the rules that say you don't show up for work drunk (even a little bit) or drugged.

24.  Lack of vision. Leaders who just position themselves at the head of the line trudging through the daily grind without imparting a sense of the big picture aren't really leading at all.

25.  Showing off without justification. Photos with B- or C-list celebrities, diplomas from unaccredited or questionable colleges, certificates from every weekend training program--nothing fails more than an unimpressive attempt to impress.