Best reason ever for supporting a football team (because isn't your team as arbitrary as everything else?) :
About as remote as you can get in São Paulo state, where the paved road ends and a dirt track goes off into the bush, but still only a few hours from the city, you can still find the odd Indian village. A friend of mine is a lawyer, and she has taken up a case for land rights on behalf of some Guaranis.
They all support Palmeiras (="palms") in the village. The old Indian guy explained: the palm tree is sacred to us. The world was born from a palm tree. We eat palmito (palm heart). The birds which are messengers of the spirits perch in the palm tree.
Therefore, we are all faithful to Palmeiras.
Oh and I met Sócrates, Brazilian football legend from the 70s, in the bar a while back. These days he is getting a bit alcoholised and he was completely sloshed. Like Gazza. I asked him what he thought of English football.
"It's a load of shit," he said. "Just like the football in any country."
[From a more-or-less indifferent football fan in England I have become a complete devotee in Brazil. Just like I follow cricket when I'm in India or Pakistan - it is very difficult not to be caught up in the feverish excitement. I used to make money betting on the cricket in India, back when Pakistan was still a team to be reckoned with, because no matter how poor the chances, it seemed to be utterly inconceivable to people that anyone would want to bet on Pakistan (ancestral enemy...) winning. Not only that, but in Brazil it's a different game, a beautiful virtuoso game compared to the tactical workmanlike football of Europe.]