April 3 (Bloomberg) -- Neil LaBute’s ferociously funny “Reasons to Be Pretty,” about fragile human relationships and the seemingly inconsequential details that threaten or even wreck them, has traveled successfully from New York’s Greenwich Village to Broadway despite changes in cast and text.

Greg, a bookish warehouse worker, has been living with Steph (for Stephanie), his high-school sweetheart, for four years. They are friendly with Kent, the former high-school bully, now at the same warehouse, and his wife, the pretty staff security guard, Carly.

During a conversation with Kent, in Steph’s absence, Greg has let out something about his girlfriend’s looks that Carly overheard as “ugly,” though he insists that he called them merely “regular.” Carly has informed Steph of Greg’s alleged insult.

The play begins with a bruising bedroom fracas, during which the wounded Steph hurls thunderous imprecations liberally laced with obscenity at Greg, who parries with equally vehement protestations. It is a scene as funny as it is furious, and a similar mixture of the ludicrous and the lamentable runs throughout.

Friendly Fire

Greg and Kent play on the same company baseball team hungry for a trophy and chat with an amicable prickliness during their lunch breaks. At one such, Kent, who has impregnated Carly, reveals that he is having an affair with Crystal, a sexy new worker, something Greg must reveal to no one, least of all Steph, who has moved out of their shared quarters.

Various loyalties are severely tested as the play shuttles between volatile comedy and vicious rancor. LaBute excels at quicksilver mood changes as every relationship conceals mines of hostility waiting to explode. One wrong word suffices to detonate them, and no one makes better antagonists than lovers or spouses.

The dialogue couldn’t be snappier and psychologically more astute, as partings prove as fraught as pairings, with the bitterest resentment harboring nostalgic yearnings for reconciliation.

This requires utmost versatility and agility from the young actors, who must be able to go instantly from fireworks to waterworks, as well as display emotional ambivalences with a prestidigitator’s skill. Under Terry Kinney’s clockwork direction, the cast spiritedly obliges.

Ambitious Nerd

The two holdovers are Thomas Sadoski, whose Greg is appropriately at the crossroads between laissez-faire nerdiness and intellectual ambition; and Piper Perabo, whose Carly, though as staunch as she is pretty, is not free from vulnerability as her suspicions justifiably increase.

New are Marin Ireland, whose acting is as apt as was Alison Pill’s, although not as good at winning audience sympathy; and Steven Pasquale, whose Kent is both more charismatic and more amusing than that of Pablo Schreiber, his predecessor.

David Gallo’s sets continue to be adept at quick changes of location, Sarah J. Holden’s costumes are immaculately down-to- earth, and David Weiner’s lighting pulsates with nice nervousness between scenes.

The now-omitted soliloquies, which seem to me LaBute’s only real Broadway change, are not greatly missed. The sophomoric yet provocative ambiguities are plentifully present in story and dialogue.

At the Lyceum Theatre, 149 W. 45th St. Information: +1-212- 239-6200; http://www.telecharge.com. Rating: ***

What the Stars Mean:
****       Excellent
***        Good
**         Average
*          Poor
(No stars) Worthless

(John Simon is the New York drama critic for Bloomberg News. The opinions expressed are his own.)

To contact the writer of this column: John Simon in New York at jis1925@aol.com.

Last Updated: April 2, 2009 22:30 EDT