I drink about every weekend when I go out. And if I do, I usually don't drink the next day as my body just rejects the idea if getting trashed a second day. During the week I don't usually go out much so I don't drink the hard stuff, unless I'm at a happy hour. But I will have something like wine or whatnot if I've had a particularly hard day.
Do I need to drink to have fun? No, but when you're at a club or a bar the drinking (to me) kinda makes sense.
The problem with dependency is tolerance, mental issues, and physical will power. No one becomes an alcoholic overnight, unless there's a genetic proprensity for alcoholism due to your parents and grandparents being slushes. It happens as you build your tolerance. Consider this, when you first started drinking a beer or two would get you drunk (not included in this argument is the whole body-weight/metabolism factor). You keep on drinking and as months/years goes by it now takes you, say, 5 beers to do what those 2 did. More time passes and it takes you now 10. So you keep drinking more and more trying to get the same affect, meanwhile your body is getting accustomed to the alcohol in your system.
This doesn't make you an alcoholic, though, as this is a normal process. But add that to mental instability (in terms of needing alcohol to fill certain needs or anxieties), and the cocktail for an alchy is born.
