What qualities make a good leader and more importantly what makes a bad one?
Leadership is not about trying to force people to follow you but knowing how to get them to follow you because they want too. Basically you present to them a way forward or goal which they both agree with and which if they choose to follow you will see them get their needs met.
In a workplace context the gold standard is Maslow`s Hierarchy of Needs and Hertzberg`s Hygiene factors. Along with that training and development plans leading to future promotions. You also have to be altruistic towards your staff and look after them.
Bad leadership is any action which leads to the employee resenting you instead of wanting to follow you. So no shouting at them, bullying them, forcing them to do stuff, being disrespectful to them, exploiting them, etc. Treat them correctly and with respect instead. Bad leadership is usually the result of someone who doesnt know how to lead or someone who is too self-absorbed to treat the people under them correctly.
If you have a look at McGregor`s Theory X and Theory Y styles of leadership then Theory X is bad leadership while Theory Y is good.
With Theory X there is no respect towards the employee causing the employee to resent the leader and become demotivated. Because the self-absorbed leader cannot see themselves as the problem what happens is they become convinced the employee is lazy, not interested, incompetent, just after a wage packet, etc. Then the shouting, coercion, and attempts to give the employee a kick up the behind start. It makes the problem worse because its an even more lack of respect. Then the employee quits (and eventually the manager gets sacked for causing all the talent to abandon ship).
Despite how he is portrayed its actually Hitler who is the greatest leader in history (and by quite some margin too). If you compare Maslow`s Hierarchy of Needs against his ideology, policies, and imperialistic ambitions you will get why Germany followed him in the way that it did. From state healthcare, to breeding programs, to telling them they were special, to trying to get their country to live up to its full potential with a 1000 year Reich, its all in there.
He took care of all the psychological needs of the German people. In addition, everyone that he liked (and that is obviously not the millions he wiped out) got treated with the Theory Y style of leadership too.