We usually have beers and ciders going during game days, and sometimes some whiskey towards the end of the night. It's purely social. I've played games with drunk people before and it's absolutely no fun, though I have a shitfaced person to thank for making me never want to even see "Bang!" ever again.
I don't drink at all, so this isn't really a factor for me personally. Most of the settings I game in are dry, and most of my gaming buddies are non-drinkers as well (lots of teetotalling church types in there). But! I've had lots of friends who will have a drink or two when we play at their house. Very few of them have ever had enough at the table to impair the experience, although when it does get to that point the enjoyment goes south in a hurry for me.
I once played a game of Wallenstein at Geekway with a table full of guys who were all drinking a lot. As the only sober player there, I lost badly.
I drink beer frequently, and Game Night is no exception. I usually have from 2 to 4. It used to always be four, but I've been steering it more towards two lately. We have a pretty big mix of drinkers and non-drinkers in our group. I don't think we've had anyone get sloppy drunk, but I've been close on a couple of occasions. I don't want my enjoyment to diminish anyone else's fun.
I also host a full Game Day about every other month, and alcohol isn't allowed at those events.
One of my worst boardgame experiences in recent years involved a drunk player. On top of being drunk, he has also smoked enough pot over the course of his life that you can tell just by his voice. Anyway, I showed up for one of the semi-regular goth potluck dinners with some games. The drunk stoner proclaims that he loves boardgames, and his enthusiasm helped bring others to the table. We played Cosmic Encounter and Sons of Anarchy, but both games dragged for the following reasons:
1. Drunk stoner forgot the rules each turn and needed coaching through his turns.
2. Drunk stoner sometimes would get up and wander away from the table for a while, requiring a player to fetch him back for his turns.
3. Female friend of the drunk stoner finds him and sits down on his lap, creating a significant distraction but at least putting a stop to the wandering away.
I didn't bring any games to the next potluck, so of course drunk stoner doesn't show up for that one.
I'm a very social gamer, but currently don't mix drinking with gaming because alcohol puts me to sleep; I need caffeine for gaming.
My alcohol consumption these days is ~two fingers of whiskey on Friday and Saturday night after the wife goes to bed; it's a struggle to finish the glass before my eyes close.
Now that my 20s are over and I moved out of the house with two guys, I drink a lot less- this includes game night. I'll have maybe 1-2 drinks per week unless there's some kind of family celebration. As noted above by Shellhead, I had just two drinks while DMing for D&D 5e and I never want to do it again. I need to be sharper than that. I also don't think I'd want to teach or learn a game if anyone involved is noticeably impaired, unless it's something real simple like a dexterity game or Skull.
Oddly enough, my parents' house is the most likely place for me to have a drink or two with dinner, because my dad always offers wine. Sometimes we'll play Catan, Avalon, or Codenames after eating.
Depends on the game. If we are playing something complicated - no reason to be drinking. But if we are playing Crossbows and Catapults - bring out the drinks.
I don't drink at all when gaming anymore unless its a really light game. I will generally stay away from drinking if there is a game planned. I drink when socializing a fair bit and if I start drinking while playing I'll wander more into socializing and be distracted from gaming.
I don't drink often, and I don't game often but when I game I drink. I have enough experience with beer that I know what I can handle. I tend to be a high functional drunk anyways, so not a big difference between sober me and drunk me at the table, drunk me is a little nicer probably.