I'm 32 and I don't drink. I can definitelt say I don't know what it feels to be drunk, let alone having a hangover, because I have never gotten drunk. At most I have tried couple drops maybe every 2 years, usually during Xmas time or similar, when my family make me try some wine or champain, but I hardly can taste it on my lips and enough. These sips is what I have at most drank in my entire life, but to me the taste puts me off. So it was basically about the taste in the beginning. Then still the taste, but I was aware that it was in a way positive me not being attracted to alcoholic flavor (never got used in my teens, so then it was too late...).
Water in the pub/bar? As if there were not other option... it's funny. People are so fixated in alcoholic drinks, they forget there are other options, like juices, or ginger ale, or other non-alcoholic exotic drinks, or juices, or red bull or sodas (if you prefer that not so healthy option!). I have seen how friends wouldn't go to the pub because they couldn't drink. To me that made no sense.