Philosophy -- learn to see things from different angles, different philosophies. Most importantly, observe how others in your class react to discussing touchy philosophies and concepts, like religion and politics. Learn to step outside that box, and be objective while respecting opinions, and make your own decisions. Trust me, its well worth it. Both for the laughs, and for the wisdom.

edit: Just noticed I'm echoing what many others have said. Interesting that we all had the same thought.