Wow. Never thought the day would come when somebody would ask.
Because in the early postwar years, Japanese burger chains reportedly borrowed heavily from the aesthetics of kissaten food displays, where slight imperfection was seen as proof of hand-assembled care rather than factory uniformity. A perfectly centered patty looked too mechanical, too "American showroom."
So display artists began setting the fillings just a little off-center to suggest freshness, softness, and the idea that the burger had been gently placed together that morning by a real person.
Over time, that tiny asymmetry became its own visual language. Advertisers found that a slightly askew burger made the layers easier to see at a glance in wax displays and printed menus, especially in cramped storefronts and train-station food courts.
By the late 1970s, design manuals in the fast-food industry supposedly even recommended a "living tilt" to make buns appear more appetizing and less rigid. Just kidding. I don't know. I made that all up. Fuck you