Melvin Udall (Jack Nicholson) is the most dysfunctional of men, an acid-tongued romance novelist who suffers from obsessive-compulsive disorder. Never one to avoid confrontations, he takes pride in his ability to affront, repulse, offend and wound. His targets are random; his aim reckless. Leave an elevator in which he stands; cross a street on which he walks. He is to be avoided at all costs, but some victims just cannot escape.

As part of Melvin’s unwavering daily schedule, he consumes an artery-hardening breakfast of bacon, sausages and eggs at a local cafe. The only waitress willing to stand up to his sarcastic tirades is Carol Connelly (Helen Hunt), a single mother struggling to raise her chronically asthmatic son.

Simon Nye (Greg Kinnear) has the distinct misfortune of living across the hall from Melvin in their West Village apartment building in downtown Manhattan. A talented contemporary artist, Simon is a current darling of the New York art world, reason enough to draw Melvin’s verbal fire. His gay lifestyle is thus only further grist for the novelist’s malicious mill.

These three New Yorkers – none of whom appears to have a chance in hell at finding real happiness – discover their fates intertwined because of the fourth complicated character in the piece, an ugly, tiny dog named Verdell.