By Dennis Prager, Stream contributor - When I was in graduate school, I learned a lot about the left. One lesson was that while most liberals and conservatives abide by society’s rules of order and decency, most leftists do not feel bound to live by these same rules… Today, we watch leftist mobs scream profanities at professors and deans… We routinely witness left-wing protesters block highways and bridges; scream in front of the homes of conservative business and political leaders; and surround conservatives’ tables at restaurants while shouting and chanting at them.