1. reduced ability to tolerate stress

2. fear to delegate                                

3. the desire to be in control.

From my experience, when a manager is willing to work with these issues he/she starts to notice that in fact some things that seemed very important and urgent can actually wait, or that it's not a tragedy is they are not handled immediately.

Moreover, if they were willing to consider that people around can be trusted, or could be developed to take over some of their responsibilities, they got amazed to see how many things they could actually delegate. One frequent situation in which managers lose trust in people is when they delegate responsibility to someone, and that person doesn't fulfill the demand, or reports an incomplete work and the manager is left with the consequences (e.g., he needs to report and take responsibility for the failure to his superiors, or he needs to handle an unsatisfied client). After several attempts of this kind usually managers take the decision (often unconscious) that it is better to only trust themselves as such problems can not be delegated. And quickly enough they get to see they stop delegating.  . 

And last but not least there is a hidden fear, especially if managers are also employees, that they need to deserve their salary. And consequently, they need to have everything under control, they are working until midnight for weeks and make sure everybody sees how much they worth in the company. I know this may sound accusatory, but it is not my intention. Rather, I invite you to authentically look if you could see yourself sitting in the office 2-3 hours a day thinking about strategies and taking decisions that will affect the company on the long term. For some of  you this may seem somehow passive, or a total lack of activity, energy and so on. 

The second thing I invite you to meditate on is: the willingness to work in a team. Some of us feel we can easily work with people in smaller or larger teams. And yet somehow we always find ourselves alone. Others (employees, partners) leave us or change their minds. And the justification we give ourselves is that they were not able to assume responsibilities, or they were not willing to work hard or could not cope with the rhythm.

If you always find yourself alone, I invite you to consider you are actually not that willing to work with others as you might think. There may be barriers or mental paradigms you get confronted by and you don't even  know it.

This area of teamwork is extensive and has been studied by many managers, trainers and coaches. But I believe the most effective approach is to examine case by case. Each team has some concerns, personalities, goals and although we can extract patterns of behavior, teams dynamic have some unique characteristics.