who uses the toilet the most and why is it a problem ?

Albert Dussel uses the toilet the most. This is a problem because there is only one toilet for so many people.

Three, four or five times a day there's bound to be someone waiting outside the bathroom door, hopping impatiently from one foot to another, trying to hold it in and barely managing. Does Dussel care? Not a whit... He never deviates or lets himself be swayed by the voices outside the door, begging him to open up before a disaster occurs.