All managers make mistakes; good managers acknowledge and repair

IME the gap in management between ICs is accountability. It's easy to say you are sorry, or say things won't happen again but good management, and what I strive to do is hold myself accountable.

To me, that means 1. To identify the issue that occurred (especially when you caused it), and much more importantly, 2. Put systems into place that prevent it from happening again.

Employees can feel very clearly when a manager lacks accountability and as part of mid and especially high level management (if your goal is actually improving both output and quality of people's lives) to not just say you did something wrong, but actually put your skin in the game ensuring what happened will not happen again (usually it means being better at saying no or aggressively managing prioritization rather than heaping additional tasks on people).

> Put systems into place that prevent it from happening again

In addition to what you said overall, I think bad managers can have all sorts of qualities, but imo the worst ones correct for mistakes to protect themselves or people's impressions of them, leaning highly neurotic, and can't deal with conflict well, so they put in arbitrary systems in order to indirectly deal with any one-off grievance or mistake. Bad managers won't evaluate or re-evaluate the systems they put in place because they put them there to protect their ego.

"Surely this employee is underperforming because I don't like how they're performing and we have a system for that!"

They struggle to adapt to their new job because to delegate sufficiently they need to be able to trust, and let that manifest as other people doing the tasks they might have once done without their hands in the pie directly. They might assume that part of the reason they got the job was because they're great communicators, and never consider that actually that it's just that nobody ever told them they have some growing to do.