To give a total lightweight’s perspective. By lightweight I mean that two moderately-paced drinks with food and I’m drunk. This (combined with friends willing to buy in college) has let me experiment. For science, you see.
Stage zero: You are sober. You are likely to be eaten by a grue.
Stage one: About half a well-paced beer for me. I start to feel a little bit warmer and a little bit less stressed out. For the most part, my external senses are still fine, but you’re feeling slightly mellow - comparable to “man, I had such a crappy day at school/work/both, but now I’m driving home and I’ve got the window down and some nice music on and I’m doing a little better.”
Stage two: First beer’s done. I’m feeling flat-out relaxed, now, and my inhibitions are somewhat less than normal. I may be speaking slightly louder and somewhat more than normally, and topics which I would shy away from while sober may be approached - but still with a bit of a disclaimer (ie, “I know I’m just a godless liberal, but…”). I feel good at this point*.
Stage three: Somewhere towards the bottom of the second drink. This is when time starts getting a bit more wibbly-wobbly - we’ve been here for, I dunno, half an hour? An hour? Doesn’t matter. Those inhibitions - talking about politics, being talked into singing karaoke, talking to that hot guy - are all significantly reduced. I can still walk fine, but driving would be inadvisable and likely illegal, and bicycling is probably not a good idea, especially if it’s on anything but a flat, paved surface. Honesty becomes more pronounced at this point (ie, “Man, you know I love you, but sometimes you’re such a jackass.”)
Stage three and a half: You order the next round, thus deciding to continue to get drunker. This invariably seems like a pretty good idea.
Stage four: Hey, the floor’s kinda shifty! You can still walk, but with a bit of difficulty. Your speech is probably starting to get slightly less than coherent, though not terribly, and you can’t really tell. If you can tell, you don’t really care. For me, this is the point where I inevitably start insisting that if I’m sober enough to claim I’m not too drunk, then I’m not really that drunk. This is when a bartender or other server theoretically should cut you off, because you’re obviously inebriated.
Stage five: Walking becomes a struggle, so you and your buddies may link arms for support (singing may or may not be involved with this; there’s a theory that it helps your motor skills). This is the part where you want to lie down, because the world is moving an awful lot. It’s getting hard to keep track of things happening around you. This is, in my experience, when a responsible bartender or server will tell you that it’s time to call a cab and head on home.
Stage six: This is the “holding onto the grass so you don’t fall off the earth” stage. Keeping track of things going on around you is very hard. This is when the vomiting is likely to start, if it’s going to happen. This is probably the point when, if drinking at a private residence, your responsible friends will tell you that it’s maybe time to pack it in.
Stage seven: There may be some gaps in your memory the next morning. This is the point when, if you are me, you can ask for another drink, be handed a glass of water, and not really notice the difference. Any significant mental concentration or anything more than stumbling around a bit is pretty much impossible, and it’s going to be glaringly obvious to anyone around that you’re completely wasted. It’s not necessarily unpleasant at this point, but there will likely be some manner of regret (whether “Oh god my head just kill me now” regret or “Oh god I did what?” regret) once you’ve slept it off.
Stage eight: You have been eaten by a grue. Seriously - this is the point where it’s way too much and you’re putting your health in significant danger, and there’s really nothing good happening here.
*Usually. There are rare times when someone starts feeling crappy around this stage; that’s not a night that’ll go well.
