The way that the body processes and breaks down alcohol is fascinating. It's well-known that, for example, many Japanese people can hardly do it at all and so get very drunk, very quickly. But, and I can't find the citation for this, lots of people with celtic ancestry are missing a key enzyme in a later stage which is why they tend to get worse hangovers. Certainly the case for me in contrast to my more Germanic frends: if I have more than my "limit" the next day is likely to be a complete washout, whereas they often sleep it off*.
* Actually it's known that alcohol disrupts sleep, but differently for different people.
Biting the hand that feeds IT
