I probably should have been a Packers' fan, given that my whole family on my mother's side, as well as my brother, root for Green Bay (my dad rooted for the Baltimore Colts, but once they first ran Johnny Unitas out of town and then left Baltimore altogether his fandom didn't go with them and he hasn't been really interested in any one NFL team since), but the first NFL game I remember watching, the Packers against the Cowboys in either 1992 or 1993, the Cowboys won. Thus, like any little kid, I bandwagoned onto the team that won so I could hold that over my little brother's head.
Apparently that decision today looks like a mistake.
I will say that the Packers are probably my #2 team, and I don't really hate any of the teams that the Cowboys are rivals with. I pity the Redskins and their ever-increasing ineptitude, I enjoy that the games the Cowboys have against the Giants are almost always competitive and pretty rough-and-tumble, and I have enough friends who are level-headed (possibly cynical?) Eagles fans that I don't really hate them either (though ESPN's slobbering all over them is a bit obnoxious). I was never really indoctrinated to hate the Pittsburgh Steelers either, though admittedly it's easy to not like Ben Roethlisberger as a person.
I do, however, maintain an inexplicable hatred of the new Cleveland Browns, and I do not know why.
/threadDerail