Since celebrities make lots of money, they usually live in expensive mansions. Only a small population of the country can afford to live in these mansions. That is why so many celebrities live in the same neighborhoods. It is funny to see that these celebrities may go next door to ask for a cup of sugar to another celebrity.
Martha Stewart has a summer home next to Jon Bon Jovi. So, if Jon needs a cup of sugar, he could definitely ask his next door neighbor because she would most likely have extra sugar on hand.
Ryan Reynolds and his wife, Blake Lively actually live next door to another celebrity couple, Jessica Biel and Justin Timberlake. Many celebrities live in the same small radius as others.