Wasn't really old enough when the Seahawks came into existence to be a solid fan of another team, so I grew up a Seahawks fan. Of course, I was the only one in my family, and other real 'Hawks fans were few and far between. Football just wasn't much of a thing around the community I grew up in. Because of that, I didn't develop a really rabid Seahawks-only fandom at an early age. Now, definitely! Then, well, it was not quite the same thing.
I do remember in the early '80s, my mom used to get jars of Fischer's Peanuts that came in neat NFL glasses. They're worth about ten bucks or so on eBay now. I of course got the Seahawks one first. But Mom wouldn't buy me more than one of the same mug. "You need to collect all the different teams!" Still a bit surly about that point. But I had about a dozen or so of these different NFL mugs. Since, I've given all of them away to friends of mine who happen to be fans of those teams, so it worked out well. Still wish I had more of the Seahawks ones, though.
During the early years when we sucked, I always enjoyed watching Montana, Rice, Lott, Clark, Craig, and all those guys. Man, they were good! And they always had such a rivalry with the hated Cowboys that I was a bit of a fan. Never really a true fan of them, but they were pretty much my NFC team, since their play rarely affected the Seahawks, and it didn't matter to the Seahawks if they did well. The switch to the NFC pretty much killed that. And, of course, the 49ers of the current era are a totally different team and easy to hate.