Explain why buildings are wired using parallel circuits rather than series circuit?

A simple example, and it basically relates to buildings, is in Christmas lights strewn on the Christmas tree. If your Christmas lights are in series, if one bulb becomes duff, all the other bulbs also go out. So which bulb is duff (dead)? By testing each bulb you will eventually find the duff bulb and replace it.
If the Christmas lights had been parallel, one duff bulb would not affect the other bulbs. It would be very apparent that the only dud bulb (not lit) in the parallel circuit needed to be replaced.