Great rivalries are supposed to develop over time. Players come and go, fans grow old and bring their children, the games continue. Longevity is the appeal.

The New York Red Bulls and D.C. United have played 95 times since 1996, with United prevailing 43 times and winning 13 Atlantic Cup titles to the Red Bulls' 11. The Seattle Sounders-Portland Timbers rivalry dates to Seattle's 1-0 win over their southern foes on May 2, 1975. In total, they've played 102 matches across 44 years and five leagues, which equates to roughly three generations of bad blood and bruising tackles.

Then there's LA Galaxy vs. LAFC. It will have been just 572 days since the start of El Trafico when the two squads meet in the Western Conference Semifinals on Thursday at Banc of California Stadium (10:30 p.m. ET, watch live on ESPN). It took a little more than 18 months for these matchups to morph into one of MLS' strongest, tensest and most entertaining rivalries, with this week's game -- the first with real stakes -- promising to add to the rapidly developing plot. Get your tickets if you can.

Cheapest single ticket right now for El Tráfico VI with fees is over $300 on the secondary market.

...Also known as the price of two (Bundesliga) SEASON tickets at FC Bayern. pic.twitter.com/hAAj1HEsI2

— Zack Goldman (@ThatDamnYank) October 21, 2019

It's remarkable how quickly El Trafico has become a thing, but it shouldn't be all that surprising. Consider the squads. The Galaxy always thought of themselves as MLS' glamour franchise. They wanted to be the U.S.'s answer to Real Madrid, an American Galacticos that could export itself internationally. This is the team of David Beckham and Hollywood, a five-time MLS Cup winner that never wavered in its ambition, even if the results on the field suffered. The team projected style and class and largesse, regardless of results.

Then LAFC showed up, all black-clad and badass, bringing a downtown cool. This team was a startup that had history with the Chivas USA fanbase, only with a team and a front office that made all the right decisions. Banc of California Stadium, located just off the freeway and near public transportation, exudes confidence and embodies what MLS needs to be in 2019 and beyond. If the Galaxy wore the crown, LAFC were coming for it -- and coming for it fast.

The games between the two helped. In that first match, Carlos Vela scored in the fifth minute and again in the 26th while a Galaxy own goal saw LAFC jump to a 3-0 lead. The Galaxy clawed back through Sebastian Lletget, then Chris Pontius, down a goal with 15 minutes to play. Enter The Lion. Zlatan Ibrahimovic, less than 48 hours removed from landing at LAX, scored a laser from deep in the 77th minute, then won the game in stoppage time.

"Since an MLS Cup, I haven't felt that much energy," Andrew Alesana, a capo for Galaxy supporter group the Riot Squad, said of the match.

In the July rematch, LAFC again jumped to a 2-0 lead, only to watch goals from Romain Alessandrini and Ola Kamara after the 82nd minute tie the match. In August, Zlatan scored first, Vela tallied a penalty kick, and the teams tied. The Galaxy finished 2018 one point out of the playoffs, and those three matches with LAFC were the highlights.

Move to 2019, and there's a narrative that LAFC can't beat their rivals. A 3-2 loss at Dignity Health Sports Park did nothing to change that, especially considering that Bob Bradley's side had been the best team in the league by far up to that point. A wild 3-3 late August affair, featuring five first-half goals and a 53rd-minute equalizer from Vela, was the last match before Thursday's meeting. Tally so far: two Galaxy wins, three draws and zero LAFC victories.

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That's fun and all, but a good rivalry needs more than exciting games to attract the casual fan. It needs characters and villains. El Trafico succeeds there, too.

It starts with the big man. Ibrahimovic talks the talk and walks the walk. He's a physical specimen unlike any other that MLS has seen, a goal scorer nonpareil and kind of a jerk in the (mostly) most wonderful ways. There's a real venom in his comments about LAFC, an obvious dislike that occasionally crosses the line. On the other side, there's Vela, an elite enigma with the league's best left foot hidden behind a grinning, aloof expression. He's the MLS equivalent of ¯\_(ツ)_/¯ -- maddening, brilliant, whatever. Ibrahimovic and Vela get there in different ways, but they are equally captivating, and the rivalry benefits.

As for the name, well, El Trafico is a name that's perfect, dumb and perfectly dumb. Bob Bradley isn't into it, and that's fine. He's probably not wrong. It is silly. But it's memorable and special, too, something that stands out in a league dominated by FC this and United that. It is, like the rivalry itself, growing into something special.

Seattle vs. Portland boasts the history and the passion, and the Cascadia Cup is a thing of North American soccer brilliance. The Atlantic Cup, contested between D.C. United and New York Red Bulls, has some of that same flair. Same goes for the California Clasico (LA Galaxy vs. San Jose), Hudson River Derby (NYCFC vs. New York Red Bulls), Rocky Mountain Cup (Real Salt Lake vs. Colorado Rapids) and, even now, Hell is Real between FC Cincinnati and Columbus Crew SC. These all have their moments, occupying special places in the hearts and minds of an MLS club's most rabid supporters.

But if you're a neutral, El Trafico is perfecto.