In the U.S., anything at < 0.5% ABV is classified as non-alcoholic. There are many true 0.0% options, but even if you chugged a six pack of stuff hitting the 0.5% ceiling, that's less alcohol than in a single light beer. Getting even a mild buzz on NA beer isn't a realistic possibility. (Plus, practically speaking, the beauty of NA beer is that, since you aren't drinking to get drunk, you are no longer going for volume anyway and you can just nurse a drink or two and savor it.)
Similarly with poppy seed buns, technically they contain morphine (you can test positive on a drug test, there are documented cases) but the amount is so small you'd have to eat your own weight in buns to feel anything and would probably feel more from the gluten.
I used to drink a LOT. In my 20s I would drink 18 pints on New Year's eve, and regularly polish off 5 cans of Special Brew or the best part of a bottle of jack at least 2 nights a week.
Unfortunately this is good for neither the brain nor the body. Alcohol is basically a poison with a desireable side effect (though personally I hate the feeling of alcohol in my system these days). Your body rebels against it, stops digesting, healing and other things and diverts all available resources to getting the poison flushed out of your system.
Alcohol also increases the effects of GABA and suppresses glutamate. When the alcohol wears off the glutamate rebounds and the GABA receptors suddenly don't know what to do. This is normally why we get hangovers but I believe the effect can last longer. Alcohol is a depressant and really messes up your body's chemistry so it's no wonder this would have effects on brain and mood even days later.
Beer actually makes my nose clam up and I start sneezing, although I'm not allergic to yeast - I think at some point I became allergic to alcohol. Strange how you can go from being a big drinker to really not liking the stuff at all! I drank a bottle of wine and some whisky at Christmas, I still shudder at the memory, haven't touched anything since. I have no idea how people go out and enjoy alcohol now, even though I used to do it myself to excess
