'76 playoff loss to the Raiders: I was in 5th grade and knew the Pats got screwed by the refs, I was mad for days. That was the first good Patriots team, nobody rooted for the Pats then, it was all Dolphins, Steelers, Cowboys, and if you bought a football it probably had Joe Namath's name on it.
'06 AFCCG loss to Colts: Troy Brown just dropped, he just dropped it, the 3rd down pass that would have sen't them back to the SB.
'10 loss to JESTS: They simply played awful in a winnable game.
'78 loss to Oilers: Game was over by the end of the 1st quarter @#$%#$$# Chuck Fairbanks
The following year, his division-champion Patriots seemed poised to challenge for a Super Bowl berth, but just prior to the final regular season game, Sullivan suspended Fairbanks for again breaking a contract by agreeing to serve as head coach at the University of Colorado beginning in 1979. Fairbanks was reinstated for the team's first playoff game (and the franchise's first-ever playoff game at home), but the second-seeded Patriots lost 31-14 to the fifth-seed Houston Oilers.
Paul Zimmerman, Sports Illustrated's dean of professional football writers, has speculated that the animus surrounding Fairbanks departure from New England stemmed from the fact that, unlike the late-season departure of New York Jets coach Lou Holtz for Arkansas in 1976, "no one" felt Fairbanks "was a really nice guy."
'96 Loss to Packers in SB Despite the focus all day being on Parcells leaving and the beginning of the Favre media lovefest, thought the Pats had a chance until Howard made that return.
Edit: '07
After the Eagles and Ravens narrow escapes I didn't think this team was invinceable, the season had taken on a surreal quality that wen't beyond football, by the end I was just glad it was over.