I will never accept the first floor as being the second floor.
The ground floor is the ground floor. It is the same level as where you enter and every other floor is relatively up or down from it.
Most of the time I don't care what conventions people use. No system of measurements is right or wrong, it's all a matter of what you're raised with. But this is one of those cases where the convention used by a lot of people is simply wrong and I won't accept it.
The right three systems make sense, the first two are so un-logical they should be banned.