Norman Wexler, who went on to encapsulate the zeitgeist in SATURDAY NIGHT FEVER and to create deathless, hyper-offensive camp in MANDINGO, was a prince among hot-button-pushers in JOE. When a Madison Avenue type (Dennis Patrick) throttles to death the sneering drug pusher who was the lover of his daughter (Susan Sarandon), he meets an unlikely fan and friend: Joe Curran (Peter Boyle), a racist, hippie-hating hardhat type who's as far from the genteel Mr. Compton as warm root beer is from gravlax and eggs. The movie is as flummoxing, and as weirdly elating, as a deeply abusive boyfriend. One minute it's getting you to giggle along with the no-baloney Joe; a second later, he's a Hitlerian psychopath. At times, we're touched by the friendship and mutual respect that crosses class lines; at other times, we're made to chuckle at Joe and his wife's homely ways, and at still others Compton's brand of magazine-derived good taste comes in for a beating. Like another surprise hit of its year, PATTON, JOE has that non-lecturing, read-it-this-way-or-that quality. Nearly every scene has something for an audience to cheer or boo (and oftentimes, those are the same things). The director, John G. Avildsen, has a few real winners (SAVE THE TIGER, NEIGHBORS) in his undistinguished career; this may be tops among them.