That was opening day against the hated Dolphins. The Bills had not made the playoffs the previous 5 seasons and had a losing record each of the last 4 seasons. In addition, the opponent had beaten the Bills 20 straight times.
Well that day the Bills opened some eyes defeating the Dolphins 17-7. The team went on to start the season 5-0 before ending up 11-5, earning their 1st playoff berth since 1974, ushering in a new (although too short lived) era of winning Buffalo Bills football. The pent up frustration of the fans was so evident on that day, that when the game ended, the fans stormed the field and tore down the goal posts, ON OPENING DAY! I've never seen this before or after and in today's era of added stadium security, will never happen again in an NFL game.
Just like that day in 1980, the Bills are in a long playoff drought playing a team that has owned them (Patriots 10-1 last 11 games). While there won't be any home field advantage, or fans storming the field, with the start of a new season, I can dream of today being the 9/7/80 of the 2000s.