Sometimes, tradition, proximity and raw hatred spawn rivalries. Sometimes, though, rivalries come from two teams regularly fighting to become the best in pro football.
The Packers-Seahawks series has become such a rivalry. In this quarter-century of excellence the Packers have enjoyed, it ranks alongside the series with the Cowboys and 49ers rivalries in the 1990's as a showdown that often has decided which team belongs among the NFC's elite.
The rise of this rivalry truly began with the departure of Packers coach Mike Holmgren to the Pacific Northwest in 1999.
As the Packers returned to playoff status early in the 2000's, Holmgren developed Seattle into a contender. The teams met in a 2003 NFC Wildcard game at Lambeau Field which included six lead changes, four ties and one ill-fated statement by former Packers and then-Seahawks quarterback Matt Hasselbeck over the Lambeau loudspeaker.
"We want the ball and we're gonna score," he shouted after the Seahawks were awarded the football to start overtime.
Oh, he threw a touchdown pass alright...to Packers defensive back Al Harris. His 56-yard touchdown with Hasselbeck's intercepted ball, and "dreadlocks in his wake" as Wayne Larrivee put it, was the first salvo in this budding NFC rivalry.
Four years later, Holmgren came back to Lambeau with his Seahawks for a divisional playoff. After trailing 14-0 early on, Lambeau Field turned into a snowglobe, and Green Bay's men of winter responded with six touchdowns - three from Brett Favre's arm and three from Ryan Grant's running legs.
The 42-20 win in a winter wonderland was the final triumph for Brett Favre as a Packer.
The Pete Carroll era in Seattle has not been so friendly. September of 2012 brought a now infamous game on the road where the eye test on the final "Fail Mary" play showed that the Packers won, but the referees disagreed.
That incorrectly-called loss cost the Packers a first round bye and home field advantage for the divisional round of the playoffs - and possibly a lot more.
Two years later came perhaps the most debilitating defeat in Packers history, an NFC Championship Game where they owned a 16-point lead at halftime, and lost it.
(We'll spare you further details.)
The good news for Packers fans: The last couple games - at Lambeau Field in 2015 and 2016 - have gone Green Bay's way.
A 27-17 win two years ago was followed by one of the most dominant wins for the Packers over a playoff team in many years, a 38-10 triumph over the now-loathed Seahawks.
Considering the fact these two teams have each made the playoffs the last five seasons, there is plenty of reason to believe this rivalry of passion and excellence will continue to grow.