[ReptileMan]

Unlike classical grape wines, the fruit ones are quite "wet". And sweet alcohol for reasons unknown causes the worst of the hangovers.

[mofunnyman]

It's for the same reason you feel dead after eating a pound of sugar, and compounded with extra dehydration. Take it from a former professional alcoholic, drink your water and take your B vitamins.

[throwawaymaths]

is it unknown? sugar competes with aldehyde dehydrogenase.