The problem with patriotism/nationalism/tribalism is the emotion of love of one's group reaches its peak when there is hatred for another group. Ironically, us vs. them is essential to forming larger tribal units. Otherwise tribe consolidation in the last millennia (clans to city-states to nations and nation-states) would not have happened. Unfortunately, us vs. them is still essential to human unity.
Yeah, and I'm sure you have no "us vs them" hatred going when it's Roma vs Lazio, Liverpool vs Manchester United, and the Chicago Fire vs NY Metrostars!
Actually, I don't. If my favorite teams lose, even to rivals, I'm disappointed but I don't feel any hatred. Controlled and nonviolent environments like sports (usually) are perfect places for tribal passions. Yet club and national team loyalties, as one poster mentioned, are imagined communities and it is primitive for intelligent, civilized species to kill each other because "my tribe is better than yours, my tribe is special, our tribe is the chosen people, that land belongs to my tribe" etc.