What did you do, pick the team that won all the time in each sport when you were young and made them your favorite?
Since I must justify my choices to you, I guess I will.
Braves (since '92)- my first memory of watching baseball was when I watched the 1991 WS w/ my Grandpa. I was 6-years old at the time. I did not have a "favorite" team. I did not really care who won that WS. Obviously, the Twins won that year. So the next summer when I was out of school I really started getting into baseball, and there were two teams on TV every day when I was home. The Cubs on WGN and the Braves on TBS. I went with the Braves because I could not stand Harry Carey.
49ers ('94)- this one you might be able to call me a "bandwagon" fan. I did not have a favorite team, and all my friends liked the Cowboys or the Packers. To be different, I started cheering for the Niners.
Lakers ('96)- they sucked when I started cheering for them. I saw a Kobe Bryant high school game on ESPN when I was in 6th grade, and I loved the guy. I decided I would cheer for whatever team drafted him. On draft night, I thought I was going to be a Hornets fan. Then they traded him to the Lakers. The next few years were far from glorious. Then there was the 3-peat from '00-'02. Then a few rough years again before the last two years. Sadly, this run may be over soon. Oh well, it has been fun. The Lakers are the team that I am in to the most though. I have seen them play a minimum of twice a year since '02 when I turned 18 and could drive myself to games. I was even at Staples when Kobe dropped 65 in March of '07.
So, yeah, call me a bandwagon fan if you want, but I would hardly call myself that.
Bandwagon fans jump from team to team. I have never wavered, or switched allegiances. And it is not like the Braves or 49ers have sniffed a ring in over a decade.