Alcohol has been an integral component of the human experience pretty much since the dawn of recorded history. Some of the oldest surviving inscriptions and treatise actually focus on the preparation and consumption of alcohol, particularly beer. Beer has double positive of being relatively sterile and high in calories, making it an excellent way to disperse grain as part of a ration for work. Wine, on the other hand, has always been somewhat more of a 'cultured' drink in that it is more expensive to produce, and thus consumption of it is a sign of wealth. Sharing of wine is sharing of wealth and status in many ways. As to why one might consume these in the first place, the reasons today don't different substantially from the reasons two thousand years ago, that is, inebriation and good spirits (no pun intended). Because distilling was not invented at this point, wine served as the catch-all for all social purposes that we would associate with wine and hard liquor today, and various forms of wine filled these niches. It was not uncommon to mix wine with water in the ancient world for your casual drinks with friends, while drinking wine straight could be considered to be the equivalent to drinking a hard alcohol straight today.