Valentines Day is a corporate Conspiracy theory that makes guys think that they have to buy things for women to get in their pants and probably the other way around as well.
Either way, it's certainly not a holiday. It's not a holiday unless the Sex is really good.
Valentine's day was originally a Pagan Roman festival called Lupercalia. Roman Priests (not the same as Roman Catholic Priests) sacrificed Animals at a cave they thought was sacred. Then the priests who were naked except for a goat skin, went round thwacking women with strips of the hides from the sacrificed animals. Roman women put up with this because Superstitious Romans imagined this would improve their fertility.
The Romans also used to pair men and women off at random at Lupercalia and expect them to stay together during the festival. Random pairings aren't the best way to get compatible relationships. Then when Religion gets involved people aren't always sensible.   
- ↑ The Dark Origins Of Valentine's Day
- ↑ The Darkness of Valentine’s Day and its Pagan Origins
- ↑ St. Valentine's Day: Ancient roots stained in the blood of goats and saints