Employees perform their best in a rewarding and encouraging environment. Bullying and harassment in the workplace by a supervisor or a manager is never a good approach for sustained positive results.
A lot of managers and/or supervisors have this misconception that the only way to get employees to work hard and produce results is to control them with bullying and harassment. They may have some success with a few employees, but for a vast majority of employees this approach simply does not work. Making employees feel bad about themselves do not typically make them work harder or make them more productive.
All employees are aware that they get paid because of the work they do. It is not difficult for them to understand that if their performance is not satisfactory, there may be some consequences. It is the job of a manager to help each employee reach his or her potential through an appropriate supportive approach. It is important to have frequent communications with the employees so the manager can truly understand the problems faced by the different employees and then provide appropriate assistance so the employees can succeed. There can always be a few employees who simply do not want to work hard and perform well. But most employees want to do a good job and want to succeed for the company they are working for. If the managers can help them in a supportive manner (rather than in an abusive manner) most employees will succeed and that will only make the company more successful.