A woman lives on the tenth floor of an apartment building. Every morning before work, she takes the elevator down to the ground and goes to work.
When she gets back, if it is raining, or there are people with her, she will take the elevator all the way to the tenth floor.
If it is not raining, and people aren't with her, she takes the elevator to the fifth floor and then takes the stairs the rest of the way. Why?
There are ten floors in an apartment building.
Answer: She is a midget. When it is raining, she uses her umbrella to hit the  button. If there a people, she can ask them to hit it for her. But she herself can only reach the  button.