Chundles said:
Actually the primary cause of the hangover is dehydration. Alcohol is a diuretic, causing us to lose more fluid than normal via urine and sweat. The symptoms of a hangover are similar to someone who is dying of thirst. The type of alcohol has very little to do with it.
That's right, but the mentioned impurities in coloured liquors do both increase the dehydration and add a bit of headache in itself (in my experience
). Staying clear of those is a good idea, if you're planning to get s***faced...
But, the best way to avoid any unpleasantness is to order a plain soda when "last calls" are made, and drink (at least) half a litre of water before going to bed. That way you actually had one drink less than you'd have "normally", you don't get into bed with increasing while the alcohol level in your blood is still rising (which is a sure way to make the room start spinning, with all the troubles keeping those last drinks down that might cause) and last, but most important, you don't get as dehydrated as you would otherwise.
All in all, I've only had a real hangover once since I was about 18 or 19, and that was the time I broke all my rules: Drank brown liquor in addition to beer, vodka, tequila, and some gods might know what else and (probably) forgot all about drinking water... that was a hard afternoon the day after when I finally got out of bed...