My favorite story of the rivalry between the Seattle Sounders and the Portland Timbers took place back when both clubs were still toiling in the minor leagues.
The setting: a Starbucks branch across from what was then called Jeld-Wen Field in downtown Portland, where Seattle coach Brian Schmetzer stopped in with his assistants a few hours before kickoff.
Now, these were the USL days, so the blue jackets the staff wore wouldn't have been as conspicuous as they are now. Still, seated in the front window of the shop that afternoon, Schmetzer caught a passerby looking at him with a furrowed brow.
The man rounded the corner, temporarily disappearing from view. He doubled back, walked back uphill to ensure that he was in Schmetzer's direct line of vision and flipped him off with both middle fingers.
Seattle and Portland are more alike than either franchise would care to admit. As Richard Farley put it in his insightful breakdown of the rivalry last year, the two cities, cultures and fan bases are siblings, products of the same source.
As such, there's pettiness to this regional feud, eternal one-upmanship. This manifests itself in perceived slights, creative insults and memorable goal celebrations. There's depth to it, too, going back to the North American Soccer League days of the 1970s, which few Major League Soccer rivalries can touch. Ever since the NBA's Sonics left Seattle in 2008, Sounders-Timbers has stood as the lone professional sporting outlet for tensions between the Pacific Northwest's two biggest cities.
The double bird itself isn't my favorite element of Schmetzer's story. It's that it wasn't a reactionary response; the Portlander walked around the corner, considered his actions and still cared enough to backtrack to deliver his message.
That type of genuine ill will cannot be manufactured. It's the product of years and decades of mutual resentment and shared history.
Ahead of the 97th all-time meeting between the Sounders and Timbers on Sunday at Providence Park (10 p.m. ET on ESPN2/WatchESPN), below is a selection of the memorable games, fan displays and series icons that make the best rivalry in MLS as distinctive as it is.
The best games | The best tifos | The biggest icons