Bad managers yell at you, in front of everyone and when they realize they were in the wrong, bad managers can't apologize.
Bad managers can only find things like straightening wall decorations in the office to do when everyone else is working.
Bad managers ask you to show them how to do a part fo your job, then quit after three minutes "because it is too hard."
Bad managers say the wrong thing. Example: A massive layoff is never, ever a positive event when people barely making ends meet are let go. You can't twist this, in any way, shape or form. No matter how many times you say it.
A good manager supports their employees.
A good manager, even if they don't know the details of your job, respects you enough to either let you do it and soar, or asks you how so they can learn.
Good manager: Respect. Let's say that again. Respect.
A good manager is smart enough to call you out and disagree with you, and give you corrective ideas. A bad manager will just shut you down without any guidance.