I became a fan in spite of steelers fans at super bowl xxx. This isnt truly when i became a fan, i just started saying i was a cowboys fan when people asked me about football because i grew up in pittsburgh and i knew that would shut them up. Looking back, at that early age that part of my personality was done developing...
That may not be the purist origin of fandom for a team, but truly beginning to follow dallas in the mid 90s and still being here today, i feel that i am legit.
Basically, while i got to enjoy super bowl 30, i wasnt enjoying it as a dallas fan, i was enjoying it as someone in pittsburgh who didnt like the 45 hour a day 9 days a week 543 days a year coverage of the steelers.