When a person unfocuses their eyes, they do so by relaxing the ciliary muscles in their eyes, which in turn causes them to lose focus. In general, people tend to unfocus their eyes when looking at an object from a close range, when looking at hidden images — such as Magic Eye Images — and when admiring 3D imagery or artworks. A lot of people first learn the ability to unfocus their eyes during their childhood, while others simply pick up the skill while daydreaming or staring into space.
Cold and flu season, allergies, and even inhaling an irritant like smoke or perfume can cause an unpleasant coughing fit. Coughing is the body's way of getting rid of anything that's irritating the throat or lungs. It's estimated that coughs can be expelled from the mouth at speeds of up to 100 mph (via Penn Medicine)