Doors opening

The Washington Metro system is the second-busiest in the U.S. and a neat ride. The ceilings are vaulted, evoking the monumental city above it. The system is easy to use (though the farecards can trip people up). When the train approaches the station, lights on the edge of the platform blink. And when that train stops, a woman invokes, chirpily, two words all Washingtonians know.

My doors are open. Even if they don't appear so. Push through. I'm on the other side.