On those occasions when I’m forced to take the elevator (which is often, because it’s literally impossible in my office building to walk up the stairs – the door to the stairwell is kept locked), I am reminded of another Americanism: the “first” floor.
A fish doesn’t know the water, so this was something I wasn’t even aware of until I moved to London in 2005. In the US, the floor of a building which is at ground level is called the “first” floor. If you walk up one flight of stairs (or, more likely, take the elevator), you are on the second floor. I never questioned the fact that this does not, in fact, make sense.
In the UK (and many other countries), the floor of a building which is at ground level is called… the ground floor (abbreviated “G” on elevator buttons). If you walk up one story, you will find yourself on the first floor. If you walk up two stories, you will find yourself on the second floor. Now isn’t that some ground breaking logic? (Yes, pun intended.)
This of course leads to plenty of confusion when people from, err, the rest of the world come to the US and, err, want to exit a building. Confusion which is similar to that which is caused by the US’s persistent use of imperial units, the 12-hour clock, and US letter format paper, other American systems that are incompatible and out of date with the rest of the world. AMURICA.