Our bodies anticipate the effects of alcohol by a conditioned response, like Pavlov's dogs. Our brains start to release euphoric signals in response to the taste of beer, even before alcohol even gets into our blood, because we seem to know what's coming.What it doesn't seem to account for, however, is the taste of the beer. I've been known to have a beer at the end of a long day of work, and the act of pouring the beer, sitting and enjoying it helps me wind down. But the beer is always a nice, tasty craft beer. A Bud Lite or other macro-lager just wouldn't have the same impact. In fact, I'd rather just skip it altogether in that case.
(thanks to my brother, Eric Michael Gray, for the link)