Friendship among women:
A woman didn't come home one night.
The next morning she told her husband that she had slept over at a friend's house.
The husband called his wife's 10 best friends. None of them knew anything about it.

Friendship among Men:
A man didn't come home one night.
The next morning he told his wife that he had slept over at a friend's house.
The woman called her husband's 10 best friends.
Eight confirmed he had slept over, and two said he was still there.