I have always had two "favorite" teams since I was 6 years old.
The first iteration was the Chicago Bears and the Dallas Cowboys from 1977 to 1989.
This was because I grew up outside of Chicago during a period of time when the Cowboys were national darlings and very successful and my father was as die-hard a Bears fan as you can imagine...he was a literal "Superfan", had the stocking cap, the 70's style jackets and sweaters (BEFORE Ditka's version and then later the replica of the one Ditka wore on the sidelines for SBXX).
My earliest memories of the NFL are "Payton left, Payton right, incomplete pass, punt".... which essentially was the weekly game plan. During those early years, I watched both games every Sunday...we would have breakfast at 9 AM, catch the coach's Chicago TV show at 10 AM, get dressed for church at 10:30 AM, attend Mass at 11 AM and get back in time for kick-off at 12PM. Then, usually after another Bears' loss, the late game was almost always the Dallas game. Add to the mix the fact that the Cowboys played in SB X, XII, XIII and then 3 straight NFC Title Games (losing all 3 - Philly, SF, Wash) and I was a Cowboys fan during the playoffs mainly because the Bears made the playoffs only once - as a Wild Card after a FG to win in week 14 against the Giants in a snow storm before promptly being curb stomped by Dallas in the playoffs.
I dropped the Cowboys the day Tom Landry was fired - partly because it was heresy to fire that man, but mainly because as a Hard-core Notre Dame fan I loathe Pig-faced Satan Jimmy Johnson. Once Jones bought the Cowboys and hired Johnson, I stopped being a Cowboys fan and have never gone back. Back in '81, when Montana threw that pass to Clark to beat Dallas in the NFC title game I sobbed uncontrollably for a while...but I never could root for them again since '89...
That left me as a stand-alone Bears fan from 1990 through 1993...before life and my career landed me in St. Louis out of college. I followed the expansion talk and while I hated the name "Stallions" (always thought it was a roller derby or porn film gang name personally). The lease issues with Clinton, the fact that Walter Payton was part of the efforts, the drama about the Patriots possibly moving here before it turned out to be the Rams...when the news first broke that they were coming to St. Louis I was actually disappointed. I thought the Los Angeles Rams should have stayed put and St. Louis should have looked for someone else to move here, but it was a done deal and they were here.
In '95, I did not really embrace the Rams. The 5-1 start did nothing for me, the trick plays from Brooks that seemed to go well at first but were also wildly lucky, the idiot Kinchen punching the goal posts in the first half of the first SF massacre of the Same Old Sorry Ass Rams....all of it left me mostly unimpressed. When Brooks was fired and Vermeil was hired I was shocked, but I also started really following the Rams and embracing them. I was convinced that training camp '99 was going to be a huge turn around...the signings of Timmerman and Green, the trade for Faulk, the drafting of Holt....it all looked great in camp. The Green injury (Trent was the QB at Indiana the same time I was a student there) was gut wrenching....then everyone knows what happened next.
I have remained a Bears fan at heart through it all. Even though they are almost certain to never win another Super Bowl in my lifetime. As long as the Rams franchise calls St. Louis home, I will remain a fan of the team. If/when the Rams leave St. Louis, I will shrug them off like a worn out coat and never look back. They will easily fit in that space that is currently occupied by the Cowboys - a team that I once gave a shit about, followed closely, even wept over their defeat; but due to the actions of its piece of shit greedy owner had to be kicked to the curb forever. There is no second chance in my eyes. An owner stabbing the fans in the heart is the equivalent of walking in to find your wife blowing some pool boy - there is no coming back from that, ever.