Part of the appeal of Vince Vaughn has been his unpredictable, combustible demeanor; how he can shift, in a matter of seconds, from a smooth talking everyman to a screaming maniac. But in recent years, his mellowness has taken over. Those outrageous spikes in energy, which served him so well in things like "Swingers" and "Wedding Crashers" (and, even to a degree, his woefully miscast role in Steven Spielberg's "Lost World"), has ebbed away, leaving behind an actor who is more comfortable with the lukewarm waters of "Delivery Man" or, god forbid, "The Internship." The spark is gone, and nowhere is that more apparent than in "Unfinished Business," a so-called comedy that has been marketed as a bawdy, dudes-on-a-business-trip lark, but instead plays like a largely unfunny drama that snuffs out any vitality Vaughn might have possessed.
"Unfinished Business" opens with a confrontation between Vaughn's Dan...
