Michael has a history of being the polar opposite to every person that has managed him. In the case of Jo, she finds Michael's lackadaisical and unprofessional behaviours to be inappropriate, and counterproductive. As Jo has set the example of working hard and doing overtime, Michael has little reason to not mirror her work ethic. This episode should have been the episode to introduce Jo to Scranton, instead of "Manager and Salesman", as it much more focused on her and the way she affects the employees.
The end result is the stories of three men, and their dedication to their work. The most serious and capable of these three men is Darryl. After years of being relegated to the warehouse despite his competence and respect that he has from his crew, Darryl is finally given recognition for his abilities now that Jo is in charge of the company. Because of his foresight, he has been given Jim's former office.
The worst of the three men is Todd Packer, as he is based on a British counterpart that is much too inappropriate for American television. The only reason that he is still employed is because he is not nailed down anywhere, and there is next to no supervision of him. As a result, he is not affected at all by the purchase of Dunder Mifflin, or Jo's visit to the Scranton office, and is the first to be celebrating St. Patrick's Day.
And finally, there's Michael Scott. Caught in between the past and the present, deluded by his pride, and having been bought out, Michael is now forced to conform. Michael finally realizes that in order for him to continue his career, he needs to be the one to make changes that will actually gain the respect of the new boss, and to set the example for his employees to follow. This shows Jo's leadership, as her work ethic and dedication are passed down the ranks to all of the employees at the Scranton branch.