What should the manager do if he has a bad attitude towards his employees?

Do you ask from the perspective of managers or employees?

If it is the former, is the employee doing something wrong? If so, it's understandable (because you didn't say it badly). If not, don't bring troubles outside the workplace to the workplace. This will not only help solve the problem, but also hurt the hearts of those employees who work for you (not nice words, but the truth). Put yourself in the other's shoes. How do you feel when your boss treats you with the same attitude?

If it is the latter, think about it. Was the former manager like this? Or suddenly. If this is always the case, it is probably nature and can be tolerated, then ignore it. If you can't stand it, then leave. If this happens suddenly, think about whether you have done something wrong. Moreover, everyone has their own disappointments, so be considerate!