I mean, do you realize this movie got both Oscars for Best Actor and Best Actress in 1997? I mean, what kind of horrible year that must have been for Hollywood?
Jack Nicholson plays an obsessive-compulsive writer (who oddly barely ever writes) that becomes a grouchy hermit. As such, the role seems to have been written for Mr. Nicholson, who has a history of playing slightly crazy, solitary characters. Helen Hunt, who in turn has a history of playing the romantic interest of much older and much uglier guys, plays a waitress who has trouble making ends meet. The third one in the party is Greg Kinnear, the gay painter next door.
It may be fitting that the movie was nominated for the acting, but not for anything else. Someone on IMDB indeed comments that the story overall is too schmaltzy to be acceptable, but that the acting makes up for it by making every scene believable.