My son Max giggles when I say “duty,” but it’s no laughing matter. Duty is the cornerstone of negligence law.Any case begins with the plaintiff who chooses the duty he wishes to allege. The court will not bother with duties that the plaintiff has not pressed in a formal pleading. See Nelson v. Aurora Equipment Co., 391 Ill.App.3d 1036, 1038 (2nd Dist. 2009) (courts “must consider whether a duty arises …