This is surprisingly annoying where I live and some houses use the British way and everyone uses the American way in speech.

We live on the American second floor. So whenever someone new comes to visit there is no easy answer to where our apartment is: if I tell them we are on the first floor, they won’t find us looking on the ground floor. If I say come to the second floor, they may use the elevator and press 2 which will then take them to the third floor.

Happens almost every time I’m not specific enough.