I was discussing comparative holidays with a Japanese student in my "Family Life" class. She said Valentine's Day is celebrated in Japan - but women give men chocolate.
This struck me as odd, since the norm of courtship is for men to show their capacity for resource provision to women.
She then told me that there is also a counterpart holiday, White Day, one month later, in which men give chocolate to women. Originally they gave white chocolate (hence the name), but now the browner kinds are also common.
And Wikipedia tells me that on White Day, if a man merely gives as much as he was given, that signals that he wants to end the relationship. To continue the romance, he gives twice or thrice as much chocolate as he received on Valentine's Day.
The imbalance in the sociobiological universe is made right.