sozobe wrote:. It's much more fun to hate the powerful and cheer when they are finally brought low.
Yeah, sozobe, that's the main trigger. Like when dictatorships are overthrown.
Another trigger you mentioned is regional rivalries (beating the neighbor city or country, or the rival team from the same city), and that's probably the second most common.
Then, there are other types. I'll abound about mine.
England hasn't played a decent Football World Cup in ages, but I love to hate the "Rose Team". They are always overblown -by their press, and also by others-, and return home full of excuses.
América is Mexico's richest and most hated soccer team. It's owned by the biggest TV network, which has a big influence in the Federation (hence, the accusation of unfair referees) and the network narrators are openly partial to their bosses' team. With all their money, they win few championships, because of their bad vibes.
Cuban baseball team, besides being hard to beat, is the regime's favorite. It was a delight to see the Netherlands humilliate them, and to read their outrage. I'm told that after the last out of the game when the US beat them in the final game at the Olympics, the TV station went off the air. I guess Fidel was furious.