Besides the obvious choices of the Pats, Jets, and Dolphins I'm surprised no one mentioned Tampa here. I know there's not that much history between us and the Bucs but the Bills have only won one game there. The 1982 loss was demoralizing at the end of the season. Plus it was the host to Super Bowl 25.
I personally can't stand the Titans. But it was more when Bud Adams flipped the fans off versus the Music City Miracle. Their win in 2015 against them put me in a good mood that whole week.