4. No really, the laws are intense
Cognac has to be aged in barrels made from French oak from one of two specific forests. Lesser forests are for peasants.
5. That whole "VS" and "VSOP" thing is actually pretty simple
There are three main classifications for Cognac: VS, or Very Special, has been aged at least two years (Cognacs marked with three stars are also VS); VSOP, or Very Superior Old Pale, has been aged at least four years; XO, or Extra Old, has been aged at least six years (though as of next April, Cognac will need 10 years of aging to qualify as XO).
6. But there are some fun bonus classifications
Some less common terminology used to grade Cognac: Napoléon, technically aged as long as XO, though marketed as being somewhere between a VSOP and an XO; Vieux, which translates to "old" and is also a marketing term denoting a Cognac between VSOP and XO; Hors d'age, which means "beyond age," is at least as old as an XO (though could be 40 or even 50 years old), and mostly just means "ruhl fancy."