Considering the psychology of a strong finish; what are some steps to put in place towards a projects end? How would you celebrate completion?

What is your comment/feedback on this statement. Please add 1 reference. 

FYI, this is the topic of this question:Your patient safety project is finally complete on time but slightly over budget. There were a significant amount of challenges encountered throughout. The project manager, who has moved on to a new project will not hold a final debrief meeting to review successes and failures; is this a mistake? Provide a specific example to support your position.