Well, we're actually from NE Oregon. My dad in general was a Seahawks fan since their inception in 1976, as they're basically the local team.
My Bills story, oddly enough, stemmed from their playoff game against Cleveland in 1989. My Uncle was a huge Browns fan and we were at his place to watch the game. I think I was rooting for the Bills just to razz him. It was probably the first time I was interested enough to watch a full football game from start to finish. Watching Jim, Thurman, Andre, and the rest of the crew that day had me completely enamored. From that day forward, I've always been a Bills fan.
I even remember as a kid writing a letter to Jim, telling him how he was my favorite player, and what a huge fan I was. Should've seen my reaction when I received a response from Jim (the Bills or his PR team). A letter with an appreciative message, essentially a signed post card, and a 3D sports card of Jim with a little stand. That thing sat on my night stand for YEARS lol.
That kind gesture finished setting the hook on my fandom. I've been there through it all ever since.