My group is better than yours

What makes your group the ‘best’? Is this really an important concept, groups that we are part of?
I’m listening to a local radio station this morning, and the morning pair – Mark & Mercedes (is that the current status for every top 10 morning station, a pair of DJs to banter back and forth?) started talking about the TV show American Idol. They suggested that everyone phone in and vote for two of the contestants that are from Las Vegas. Not to vote for them because they are the best, or should get our votes for some other reason, just because they are from Vegas.
Is everything the best simply because it’s your community? (Tribe, family, whatever it might be called). Seems like this concept causes a lot of problems.
In the US it’s fights at sporting events – my team is better than your team stuff. I think it’s called soccer hooliganism in England when sports fanatics have to defend the honor of their club. The annual San Diego Charger football game against the Anaheim team always resulted in multiple fights in the stands as people defended ‘their’ team – I don’t get it, hos is it ‘your’ team if all you do is live in the same city? You didn’t pick the players, pay their salaries (well, ticket prices are pretty high) or participate in any way other than living there. In LV we are having problems with gangs – people wearing red are ‘better’ than people wearing blue, so let’s shoot the other guys. Last year we had some problems with high school students in one of the ‘better’ sections of town. Ended up with big rocks through the windshield of a car, smashing up somebody’s face pretty badly. The US invaded a foreign country in order to ‘give’ them democracy, because our system is sooo much better than theirs was. (I don’t know, just had to throw that last one in there).
Does the concept relate back to our early pack days? I know my two dogs find it necessary to defend the homeland, and keep other dogs, and people, that are not part of our pack away. Through intimidation (barking mostly) and action (biting ankles directly, well, they are small dogs). Cats don’t seem to care. Fish seem to chase other fish away, but I can’t tell why. Most animals carry the same concepts – keeping their area clear of similar animals that are not part of their group or family.
Is this attitude still necessary? Is it part of the individual attitude that ‘I know best, do it my way’ or is it something else? It seems necessary for people to feel they are part of a group, but why does violence seem to come into play so frequently, to either punish somebody that is from a different group, to defend your own feelings of oppression, or to force someone else to conform to your attitudes and beliefs? For some people it’s pretty extreme – die with a bomb strapped to your body to kill others that are different, crash a plane into a building or blow up a car or just throw rocks at others. Or drink poisoned cool aide because you are threatened.
John Lennon’s song Imagine seemed to touch on this area. I can’t imagine not owning things (that Communism idea is a little too far out for me) but to imagine there are no countries? How would we pick the leaders we feel we have to follow? Or am I just thinking too much again?