Whether a steaming mug, the diner's name, or a big neon "EAT," these signs were visual magnets for highway travelers. Underneath that neon glow, diners became icons of round-the-clock hospitality.

Meanwhile, the customizable neon signs seen everywhere are rarely actual neon, which is very fragile, but LED. The look is easy to DIY. No fancy design firm needed. With fewer people going out ...