The feelings and concept that you have no option but to go along with what someone in a position of power over you decides. Regardless of whether that is truely the best thing.
A classic suits-versus-techies frustration feeling. I think part of the problem is that techies often prefer long hard debates before choices are made, while the suits would rather avoid it. The suits tend to rely on intuition. But, while intuition may work well for diplomacy and sales, it does not work well for tech. But they don't know this.
Another opinion is that for a suit, the problem ends when the discussion/debate is over, so they want the discussion over ASAP. For a techies, that's when the work really begins, so they would rather have a long discussion giving a workable proposal than a short debate leaving them the task of making an unworkable solution "work".
No, MentalHandcuffs are attempts to stop you from using your mind, just like physical handcuffs stop you from using your hands. Similar to the idea of a RestrictedProgrammingLanguage which may, for example, forbid you from using recursion.
Could also be interpreted as MentalBlock?, where traditional methods or experience makes a problem difficult to solve and it becomes necessary to think "out of the box" see DecisionRoutinesWhenStuck.