Use escalators correctly
When you step into a public space, it's generally accepted that you're entering a social contract. You implicitly agree to avoid sneezing on anyone's face, hold doors open for the elderly and close your goddamn mouth when you chew. By and large, Chicagoans have pretty good social etiquette, but there's one type of place where the unwritten rules that keep our civilization intact are thrown out the window: escalators.
Stand on the right, move or walk on the left. This is an unspoken rule around the world and yet, unfathomably, people here continue to form lazy blockades while glued to cell phones and grind escalator traffic to a halt. As Midwesterners, we swallow our rage and spend the whole ride to a street level about to utter profanities or an aggressive "Excuse me." But alas, we'll probably remain quiet and then complain about it for the rest of our day. And using escalators correctly is one of the rules of living in Chicago.