Because once a Bills fan, always a Bills fan = 56 years and still going.
And, as a fan, no matter how absurd it seems, there is always the optimism of a new season. The hope that this will be the year, that someday, somehow, this might be the year the football God's shine down on this team and they make a miraculous run to the playoff despite all olds.
Its week one, and we're still in first place, there is hope (which of course, as Harlen Coben writes, "it is the cruelest of virtues").