Well, to give an intelligent guess. I would assume the chemical composition of the alcohol has to do with it along with the methods of fermentation with various ingredients therein.
Distilled filtration of pure grain such as Everclear is going to give a significantly more potent and pure intoxication to your liver and thus will essentially *** you up far too directly for your brain to make any particular by-products of emotion or behavior other than general incapacity. The rest from there is based on your general demeanor and inclination towards aggressive or passive behavior prior to consuming your drinks.
Beer on the other hand is a bit more complex with the introduction of wheat, barley, hops, sometimes fruit, etc. all mingling and chemically reacting to one another via fermentation and filtering. Perhaps the introduction to these ingredients have a little more wholesome effect to your organs including your brain, akin to a liquid meal so to speak. I'm sure anyone who has had their fair share of beers (especially stouts) have felt rather "full" up to a certain point. Perhaps this has a link to the psychological effect of being happy or at peace with one's self, much like being happy after having finished a hearty hot meal.
And wine is... a horse of another color. I'll think that one out and see what I can come up with >.>
Wines are a complicated sort. Different grapes, different seasonal harvests, soil composition, exposure to sunlight, and how long it's set to age are all taken into account when it comes to taste. So....I would assume wine is just as complex as beer.
EDIT: My brain is not happy with me ATM.