Damn, now that you make me think about it, far too many possibilities to choose from.
I was nearly comatose for about an hour after the first Super Bowl. My father, a huge Bills fan since the 60s who got me hooked on them as a kid, had just passed away a few weeks earlier, near the end of the regular season. He never got to see the Bills in a Super Bowl, and they went to their first just a few weeks after he died. The emotional mess I was in, followed by the crushing disaster of that Super Bowl...well, let's just say it sucked bad.
But as low as I was then, at least there was still hope for the team. Before last year, I actually started to feel apathetic toward the team, since it seemed like ownership and leadership were lost, incompetent, and had no interest or skills for building a real team. It seemed like we would be bottom feeders forever. That was a pretty low feeling.