12. Dr. Tim Whatley
Best-known episodes: "The Yada Yada"
Before he was Breaking Bad's Walter White or Hal, the dad on Malcolm In the Middle, Bryan Cranston's most noteworthy recurring TV role was his series of five appearances on Seinfeld as dentist Tim Whatley. We first meet him in "The Mom and Pop Store," when he throws a Thanksgiving Eve party and invites everyone but Jerry. In "The Labelmaker," Whatley is the source of the term "regifter," after he recycles a present from Elaine. In "The Jimmy," Jerry discovers that Whatley stocks Penthouse in his waiting room, and later suspects that Whatley and his hygienist took advantage of him while he was passed out on nitrous. ("Is this guy a dentist or Caligula?!) But Dr. Whatley's finest half-hour happens in "The Yada Yada," when he converts to Judaism "for the jokes." "Jerry, it's our sense of humor that sustained us as a people for 3,000 years," he says — off by 2,000 or so — and then asks his hygienist for "a schtickle of fluoride." In his final appearance, in "The Strike," he hosts a Chanukah party that Elaine calls "Studio 54 with a menorah." JENNY ELISCU