People want progress bars. In the famous paper “The importance of percent-done progress indicators for computer-human interfaces,” Dr. Brad Myers of University of Toronto found people prefer to have progress indicators. Research companies, Lightspeed Research and Kantar, did a study on progress indicators for surveys which also corroborates the idea that people want a progress bar:
Dr. Hugo Liu from MIT and Hunch.com says in his article Need to Complete, “It turns out that when you finish a complex task, your brain releases massive quantities of endorphins.”
In their book Rules of Play, Dr. Katie Salen at Parsons the New School for Design and Dr. Eric Zimmerman of MIT explain, “Without a measure of progress to give a player feedback on the meaning of his or her decisions, meaningful play is not possible.”