Analyzing the situation to determine whether poor performance is due to inexperience or newness to the work or if the person needs organizational coaching is a better approach. A problem will not correct itself unless there is feedback, both positive and negative. Staffers are not mind readers, getting an attitude or getting angry resolves nothing. Every position should have a job description to set the parameters of what is expected of each employee. Change is another thing that causes problems within an office.
Some people welcome change and are ready to jump on board.
Those people are comfortable in their roles and routines. Others who are resistant and even hostile when you change equipment, operations or procedures are often insecure about their ability to do a good job under the new system. People often accept changes more readily if they have a voice in the process. You win their commitment by including them, and you may learn something that you have overlooked. This person can destroy an office by intimidating other employees, who will leave at the first opportunity.