A woman lived in an apartment building on the seventh floor. Every morning she took the lift to the ground floor and went to her work. But when she came home, she took the lift to the fourth floor and then continued by walking the stairs up. Why would she do that?

Because she is a lilliputian. She is so small that she can not reach all buttons of the elevator. In the morning see can go the ground floor, because the grond floor button is below. But when she comes home see can only go the fourth floor, because she can not reach the other buttons.