Achieving a Sense of Completion
Achieving a sense of completion is a motivator based on our sense for tranquility and order that we feel when a task is completed or finished.
Completing a task gives a feeling of satisfaction, while an uncompleted task will keep the passionate mind engaged even when not working on the task. An uncompleted task will pull the player to finish it.
That's why runners in the Boston marathon continued running to finish the race even after the bomb blast from the terrorist attack kicked them off the path.
Here are some elements that help indicate the current status of the task, but give also instructions what to do next after a task is completed: