About 3 hours into my flight it dawned on me. I had to take a leak. I wasn’t expecting a rendezvous with great design, but there it was in the most unlikely of places. The airplane lavatory (and, BTW, why don’t they call it a bathroom or restroom or toilet — who calls it a lavatory in everyday life?).
When you lock the door the lights turn on. When you unlock the door the lights go off. Perfect. It’s sorta like being in a huge refrigerator, but in reverse. In this case when you close (lock) the door the light goes on.
Anyway, I thought it was great design. Why should two things that always happen together (lock the door and turn on the light) be a two step process with different controls? Just make it one step, one control. Lock and light, one switch. Great thinking. I wonder who invented that.