The macOS scroll behaviour quietly assumes everyone is using a Magic Trackpad — wheel mice get a stuttery, line-by-line ride and the same “natural” direction whether you want it or not. Mos sits in the menu bar, intercepts wheel events, and replaces them with a smoothed, momentum-based curve, plus it lets you flip mouse direction independently of the trackpad. Free, open-source, and the kind of thing you forget about thirty seconds after installing because the friction it removes was invisible until it was gone.