My maternal grandfather came this close to playing professional soccer: When he was just weeks away from being selected as part of the elite squad for Mexico's Club América, his father told him it was time to choose—either pursue his lifelong dream of becoming a winger or settle for the much more acceptable path of studying medicine and hanging up the cleats for good.

In a decision that he would regret for the rest of his life, he chose to become a cardiologist. In order to mend his own broken, soccer-yearning heart, my grandfather then became a soccer savant. I kid you not: he could predict the outcome of a game just by looking at each team’s formation. He knew every player’s weakness so well that he could have been a fantastic scout. But most of all he appreciated the rituals of the game.

Which brings me to the art of hating the opposition.

It must have been 1983. My grandfather’s beloved América was playing Guadalajara, the Mexican clásico. Even though my sympathies lay elsewhere (with the long-suffering Cruz Azul), my grandfather bought a couple of tickets and took me to the game. When we had reached our seats high up in the mouth of the gigantic Estadio Azteca, he looked at the field below us. “What are you doing?” I asked. “Looking for the referee and for Quirarte,” said my grandfather, referring to Fernando Quirarte, Guadalajara's fierce captain (nicknamed “El Sheriff”). It took him five seconds to locate them both. And then he did something I had never seen before in this stoic, rather reserved man. He let out two thunderous, fantastically vulgar shouts: “Chinga tu madre!” (which translates, basically, as “go fuck your mother!”). He then looked at me and, upon noticing my surprise (and delight), immediately remarked: “In football, passion for those you like is equally important as passion against those you really dislike.” He then sat down and asked for beer.

My grandfather was right: There are very few things as enjoyable as hating another soccer team and everything it stands for. Because it ends up being (mostly) harmless yet poignant, hate derived from soccer—be it from a legendary rivalry, a personal grudge or any other reason—is the best kind of hate. It might actually be the only acceptable kind of hate.