I have, somewhere in my files, a copy of a "Personality Profile" designed to be used with your fictional characters. It is, for the most part, the same useless fluff that any dating service would ask you. (And we all know how successful those are.) One or two of the questions are useful, and I don't think the exercise itself is a waste, so long as you put some extra emphasis into it. Besides, even if each novel represents its own separate universe, the number of major characters can get high enough that you want to keep track of them. That sort of thing saves you from embarrassing details later on when you screw up someone's eye color - or say their height, when you have one character looking down on another, only to realize you have the dwarf staring down on the NBA player.
I exaggerate, of course, but I know of at least one author, whose novels tie together into a single universe, who got raked over the coals by her fans for making a mistake about the color of a character's eyes. And while that says just as much about the fans (obsess much, do we?) as it does the author, it's those little slip-ups that those personality profiles (or character traits) can help with.
I'm skeptical of the traits like "favorite drink" because perceptions change with the times. I don't view the daiquiri as a particularly manly drink (visions of pink umbrellas) but they were Hemingway's drink of choice. Yes, that Hemingway. I learned this little tidbit when I looked up what a "mojito" was because I was tired of not knowing. Personally, I know the drink is "hip" right now, but drinking something that tastes of spearmint does not appeal to me. But while I don't know that it matters what my main character's preferred alcoholic beverage is (VERY good Irish whiskey, by the character has a small fortune and so can afford it), I do think that having some idea of where a character comes from is a good idea.
This occurred to me the other day as I was visiting the local "beach." I grew up along the Great Lakes (like, that could be anywhere, eh?) and I realized a long time ago that this colored my perceptions. For starters, the first time I saw the ocean I wasn't impressed. Water that stretches to the horizon? Been there, done that, pretty much the entire first two decades of my life. Likewise with this recent trip to the beach. To me, that term evokes sandy shores, warm waters (in the right season), and the occasional shell. Not, as it was here locally, rocks, beach glass, and very little actual sand. That, to me, is "shore." Not beach. At a beach I should be able to build sand castles and walk barefoot as long as the sand isn't too hot.
But not everyone thinks that way (obviously, or why else would the locals have called it a beach?) and I realized that, to a large extent, this is just a byproduct of my own experiences. Which got me thinking, what others things about my worldview are/were shaped by were, how, or even when I grew up? Those are the kind of things that need to go into a character study, and the kind of things that can personalize good characters.