Re: Well someone's been on a heavy drinking session
To this I would add that if a friend says that he knows how to make some really lovely-tasting cocktails, and these then involve much pineapple juice then avoiding them at all costs would be a very sensible course of action. The memory of the morning after such a night has stayed with me for decades (the night before, not so much).
Whisky is one beverage to avoid drinking in any amount at all if you wish to avoid a hangover. Ethanol isn't the only thing which contributes to a hangover (although it is the main cause); various other higher alcohols and methanol are also strongly involved in causing hangovers. A gin distiller will, when distilling a batch of fermented wort to make alcohol, discard the low boiling point distillate and also the distillate which comes off at higher temperatures. By contrast, whisky distillers just chuck those back into the pot for another time around, relying on the maturation process to get rid of most of the nasties.