Lift Buttons

When we walked into a multi-storey complex and we need to access a higher level. What do we first thing of? Mm.. Where’s the lift? Right!
A typical arrangement of (some of) the lift buttons may be :

By our training, I believe we know exactly what these buttons stand for.
However, just today, I wonder what gets into me, I begin to find such arrangement a little strange.

Let's look at the sequence :

. . . , 4 , 3 , 2 , 1 , -1 , -2 , . . . .

Do you know what’s amiss???

Ha.. yes! The zero is missing.
The sequence should be :

. . . , 4 , 3 , 2 , 1 , 0 , -1 , -2 , . . . .

Therefore, shouldn’t all lift buttons be :

Button zero shall refer to ground floor. :)
Mathematically, it makes better sense. But again, the process of un-learning (the existing system) and re-learning (this suggested system) is almost unthinkable.

I was talking about this silly idea to a friend. You know what? He said Germany is using my this suggested system. Wow! Am I supposed to feel clever? :P