stairways in tv shows....

so i know anyone who actually reads this, is gonna be like, ummmm.... but i was thinking about this last night as i was lying in bed. isn't it strange how in a lot of television shows, they have a set of stairs going upstairs from the living room, and another from the kitchen? i mean seriously, who really has 2 sets of stairs going up to the same floor? unless your house has like 2 seperate upstairs that aren't connected. i can only think of one friend's house who does have 2 sets of stairs going to the same upstairs. but other than that, i can not remember any others.
and then, what really gets me, is that you see them go up both sets of stairs in the tv show, but when you're upstairs, you only see them come and go from one set of stairs. take full house for example. they have the stairs in the kitchen and in the living room. yet, when you're upstairs, you only see them come up from what i'm assuming is the living room. but the craziness goes even further, because when you go down to the basement in full house, there is one way down from the kitchen. but when you are downstiars, there are 2 sets of stairs, one coming from the left, one from the right, and they both meet up in the middle. where does that 2nd set of stairs go? becasue they do use both. so i find that quite odd. i mean, i know it's tv and all, but still, how many houses are really built like that? i'm guessing it's so they can have multiple 'stage' entrances, but still, that's crazy.
another show with 2 sets of stairs going up is boy meets world. i know there are others, but i'm blanking at the moment - i can picture the shows, but not their names. so we'll leave it at that.