Lying. Some would merely ignore it as an acceptable sin. About Elly shows how it can undermine the entire infrastructure of a society. People lying to each other randomly, over the most mundane issues, without understanding the consequences of their random acts, or how their simple lies disastrously change the chain of events for others. And when they make a feeble attempt at honesty, they break into coughing spasms, or prick their fingers. The final scene, showing 7-8 people unable to move their drowning car out of the sand, is a powerful allegory on how dysfunctional this society has become.