Social drinking is very much a thing in Spain. However, most social drinking is light or moderate: walk to a nearby bar, have two beers with the family or with close friends (with free tapas, which accounts for dinner), then walk back home. In rare occasions (at least in my personal experience) things degenerate and one goes out for "just one beer" and gets back home at 5am with a vague recollection of chanting down the street.
My point is: every time that things get past the two-three beers limit in an evening, I am very conscious that I'm deviating from "social drinking" and "this is a meal" and entering "getting drunk" realm.
My personal point of view: having a responsible drink every now and then is a lot easier than cutting out completely. Here's what I do:
* If I want to enjoy a drink, I have a healthy meal with it. Can't open a second bottle of beer if the meal isn't finished, and by that point I'm full and happy.
* If I'm in a social situation where drinking is expected, I have a first drink, then switch to tap water (or sparkling water when plain water just won't do).
* More irresponsible drinking is an option. It's not verboten. However, it's reserved to very special occasions (New Year's Eve, my birthday party, a good time with friends not seen in years, …), and by the fourth beer I'm already sleepy enough to need a rest.
* On a tangent: Real tapas are *free, never paid*, and come with every drink ordered in a bar (including non-alcoholic drinks). I am certain this helps curb alcoholism to a significant degree in my hometown.
This is just me. YMMV.