Have you ever noticed that the front door of your house swings in, but the door of a grocery store or cinema swings out?

This is a direct result of “Life Safety” codes. In a crowded public space, if a fire breaks out, people panic and rush the door. If the door swings inward, the weight of the crowd pressing against it makes it impossible to open. After hundreds of people died in early 20th-century theater fires because they were crushed against inward-swinging doors, the code was changed to require all “assembly” buildings to have outward-swinging doors equipped with “panic hardware” (the push bars).