Buddy Ryan vs. Mike Ditka
Following the retirement of head coach Neill Armstrong in 1981, Bears' defensive coordinator Buddy Ryan was expected to get the top job. Instead, the organization brought in Mike Ditka to fill the void, and so began a long-lasting feud between Ditka and Ryan. Despite coaching some of the best defenses in the NFL from 1982-84, Ryan accepted the job of Eagles' head coach in 1986. When he and Ditka went head-to-head over the next five years, Ryan would confidently and consistently denounce his former team, although Ditka offered little response. Maybe that's because he went 4-0 in those games.