The Atlantic discusses the psychology of waiting in line.
Research suggests long lines are paradoxical. Sometimes, of course, they are simply annoying. Other times, however, they increase the perceived value of what you are waiting for (e.g. waiting in line for a top-notch New York City restaurant) and/or they can get your attention and make something seem attractive.
Organizations have different ways of dealing with lines and waits. My favorite is Hobby Airport in Houston. It was inundated with complaints about long wait times at baggage claim. Its response was to move the baggage claim area further from the gates, so people would spend an extra five minutes walking rather than standing at the carousel and waiting. Complaints dropped to zero.