How has Jay McInerney survived, even prospered? He's like one of those runts of the litter on a Discovery channel documentary: Not smart enough to find the teat, not wily enough to outfox predators. So sad. And yet! For decades, somehow McInerney has turned his loose-living puppy-eyed idiocy into the stuff of salary. His blog for House and Garden has recently chronicled his inability to walk functionally or to talk about anything but his failed film adaptation of "Bright Lights, Big City." The latest post catches McInerney at his best. At the end of a meal at Babbo, McInerney comes into some unpleasantness.