How best to put this?
This nexus of neurons got you through a half-day of work Friday before you feigned a scratchy throat, went home, turned out the lights and tried to channel Tommy Prothro.
Like breathing, this is a basic, involuntary, primal, rivalry instinct.
Your season stinks, you're trying to justify the tanks of gas it'll take to get you to the Emerald Bowl, you hurt in your solar plexus and relief will come only when you see rivulets of mascara dripping down the faces of anguished Trojans cheerleaders at the end of today's joy-filled UCLA conquest.
You have already stamped and licked the envelope on the scurrilous, "take-that" letter you penned to ABC's Brent Musburger for, last week during the telecast of USC's win over Notre Dame, all but ordering the limousines for USC's escort to the Bowl Championship Series title game Jan. 8.
All USC had to do was get by UCLA, as if that were like flicking a piece a lint off your tuxedo before accepting the Academy Award.
If you are a true UCLA fan, you are Andrew Purner, an economics degree on your wall, UCLA class of 1989.
When you relocated from Southern California to North Carolina a few years ago, and had the chance to name the road in front of your new home, you named it "Bruin Trail."
And no, Trojans fan, it had nothing to do with UCLA's scoreboard position in recent UCLA-USC episodes.
Purner's dog is named "Bruin" too.
Purner lays out the landscape for deep-seated contempt for one's rival.
"It goes to who your two favorite teams are," he said by phone. "It's UCLA and anyone playing USC. That's what the psychology boils down to. If UCLA was 0-11 and they won this game, in my mind that's a successful season because they take USC out of the BCS title."
That's pretty much the Gettysburg Address of Rivalry-Think.
It's almost better in years like this one, when one team in the rivalry is down and the other is the Sears Tower.
Victory becomes sweeter while the rival's pain is tenfold intensified.
Former UCLA coach Terry Donahue lost his first four games to USC before a breakthrough 20-17 victory in 1980, which was propelled by a pass that deflected off USC defensive back Jeff Fisher into the waiting hands of Freeman McNeil.
Winning on a fluke play is always preferred.
"We had to have a great deal of luck, athleticism and emotion to win that game in 1980," said former Bruins quarterback Tom Ramsey, who started the game before being relieved by Jay Schroeder.
Emotion is the key word there. It can carry a rivalry underdog no matter how bleak the outcome might seem because the other team has the receiver named Jarrett.
Texas A&M; finished the season 5-6, was inferior to Texas in every way, yet the Aggies nearly pulled off the upset before losing, 40-29. The next week, Texas advanced to the BCS title game by defeating Colorado, 70-3.
Texas outscored three teams, 198-17, but had trouble putting away its fiercest rival.
What does that tell you?
Last week, Texas A&M; cheerily denied Texas a trip to the Big 12 championship game by pulling off an upset in Austin, 12-7.
Last week, superior Florida beat inferior Florida State by a touchdown.
What's the mind-set of the potential spoiler?
Former UCLA receiver Michael Young, who played 10 years in the NFL, tried to explain:
"Here's a chance, if we can win this game, to play in a game that people will remember, a historical game," Young said. "Even though it's not a historical season, I as a player have a chance to be part of something historical. Also, it will heal a lot of wounds suffered."
Young said the key for UCLA is keeping the USC game close enough for long enough.
He calls it the "hang-around" factor.
"It comes down to how the game begins," Young said. "Emotion can truly elevate a player's performance. But it can only overcome so much. I don't see how, if both teams don't turn the ball over, I don't see how UCLA can realistically win this game.
"But what happens when emotions are high, and the momentum swings, is the momentum makes you believe you do have a chance to win. Then you can pull off these upsets. It can only happen if something happens in the first half."
UCLA needs only to look to history to find cases when a rival has crushed its rival's dreams.
Some of it is Bruins history.
* In 1959, USC was No. 2 in the nation and UCLA was 3-3-1. The Trojans outweighed the "Gutty Little Bruins" by about 20 pounds per man on the line.
UCLA won, 10-3.
* In 1965, UCLA denied Heisman Trophy-winning tailback Mike Garrett his last chance to play in a Rose Bowl with a 20-16 win. Garrett is now the school's athletic director. This time, UCLA can hurt Garrett by sending him to the Rose Bowl.
* Army had won 28 straight games and was trying to complete its third straight unbeaten season in 1950 when it faced archrival Navy in Philadelphia. Army's average margin of victory that year was 30 points -- 33-3 -- and the Cadets were three-touchdown favorites to beat the Midshipmen. Army turned the ball over five times. Navy won, 14-2.
* Ohio State was No. 1 and seeking its second straight national title in 1969 when Woody Hayes' Buckeyes were bushwhacked by Michigan, led by first-year Coach Bo Schembechler. It was, as it should have been, one of Hayes' most bitter defeats. "You'll never win a bigger game than that," Woody huffed at Bo years later at a banquet.
* The 1964 season couldn't have gone better for first-year Notre Dame Coach Ara Parseghian until he led his top-ranked and undefeated Irish team into the Coliseum against three-loss USC. Notre Dame jumped to a 17-0 halftime lead, only to watch the season unravel when USC quarterback Craig Fertig tossed the game-winning touchdown pass to Rod Sherman with 1:33 left. Notre Dame was denied its first undefeated season since 1949. Alabama won the national title.
* "Punt, 'Bama, Punt." The Alabama-Auburn rivalry is such that Auburn fans tortured Crimson Tide fans with this chant after the 1972 game. Undefeated Alabama, led by Coach Bear Bryant, blew a 16-0 lead and lost, 17-16, when Auburn returned two blocked punts for touchdowns.
It was the only regular-season defeat Alabama suffered from 1971 through 1974. Alabama exacted revenge by winning the next nine games in the series.
* Perhaps no player or coach has been more victimized by a rival than former Ohio State coach John Cooper. Three times -- in 1993, 1995 and 1996 -- Cooper led undefeated teams into the Michigan game and lost.
His 1995 team was No. 2 behind Nebraska in the polls while Michigan was unranked.
His 1996 team was No. 2 behind Florida while Michigan had three losses. Michigan won, 13-9. Victory was secured when Wolverines safety Marcus Ray intercepted a pass as time expired.
As he raced off the field, Ray screamed "I never wanted to play for Ohio State and I never will!" Ray was from Columbus.
* In 2001, defending national champion Oklahoma got back in the national title race the day after Thanksgiving when Colorado shocked No. 2 Nebraska, 62-36, in Boulder. Oklahoma only had to defeat 3-7 Oklahoma State in Norman to move to No. 2 in the BCS standings. A week before, Oklahoma State had given up 517 yards to lowly Baylor.
Final score: Oklahoma State 16, Oklahoma 13.
No one thinks pulling off an upset over USC will be easy, but oh the payoff ...
"You have to live with the anguish, and the triumphs are far and few between," UCLA fan Purner said. "But this triumph would be so satisfying it would carry you for five years."