A dozen Thanksgivings ago, I was in a Bangkok bar, repeatedly toasting the fateful and glorious meeting of Pilgrims and Native Americans with a group of bewildered but willing locals. On the screen above me was a tape-delayed broadcast of the Steelers-Lions Thanksgiving game. When the contest went to overtime, Pittsburgh’s Jerome Bettis was invited to call the coin toss in the air. Bettis said tails (or possibly “hea-tails” ). Referee Phil Luckett heard him say heads and gave the ball to Detroit, upon which the Lions went down the field to score and win the game. At that point, plastered and confused, I decided it might be a good time to stop drinking.

The events of that fateful Turkey Day had repercussions beyond my sobriety. In the wake of the game, the NFL mandated that heads or tails must be called before the coin goes tumbling through the air. Prior to the 2010 season, the NFL made a far more significant change to the league’s coin toss rules: Starting with this postseason, the winner of the overtime flip cannot win a playoff game with an opening-drive field goal.

These new regulations were met with widespread acclaim—it was about time the league had struck a blow against the coin, pundits crowed . It’s not just the NFL. These coin-toss changes are part of a larger trend to try to eradicate luck from sports. League poobahs have introduced modifications great (instant replay) and small ( NASCAR’s green-white-checker finish ) in a quest to eliminate arbitrariness from our games. We hate the idea that one-in-a-billion athletes, with all their training and coaching and practicing, are as buffeted about by the fates as the rest of us. Indeed, we relish sports precisely because they transport us away from a world so often governed by forces outside our control.

The sports world, however, wasn’t always so uncomfortable with randomness. Coin flips used to be a far more pervasive, far more accepted part of our games. Between 1966 and 1984, for example, the NBA flipped a coin to determine whether the Eastern Conference or Western Conference would get the first pick in the draft. Thus Lew Alcindor became a Milwaukee Buck, Hakeem Olajuwon a Houston Rocket , and Magic Johnson a Los Angeles Laker. Surprisingly, there wasn’t much whining on the part of the losers—maybe the Chicago Bulls didn’t want to make David Greenwood feel like a consolation prize when they lost out on Magic.

A coin toss hasn’t just affected the fates of NBA franchises. Were it not for a coin landing heads, Terry Bradshaw would have been a Chicago Bear and the Pittsburgh Steelers likely would not have won the most Super Bowls in NFL history. Baseball history, too, has swung on the whims of currency. Think the All-Star Game is a strange way to determine home-field advantage in the World Series? Let’s take a trip back in time to the dead-ball era . Until 1925, the site of a potential Game 7 was determined by, yes, a coin. There was a relative paucity of all-or-nothing games, though, as the toss only determined the location of a Game 7 three times—in 1909, 1912, and 1924. After John McGraw’s Giants lost the toss (and the seventh game) to the Washington Senators in 1924 , the rule was changed to rotate home-field advantage between the two leagues.

A fortuitous toss of the coin is also a key scene in the hit sports movie Secretariat , in which the good people at Disney manage to turn one of the most dominant thoroughbreds ever to put hoof to track into a plucky underdog. Ironically enough, the part of the film that most seems most like cinematic balderdash is absolutely true: Penny Chenery, the steel-tipped doyenne played by Diane Lane, did indeed win the rights to Secretariat as the result of a coin flip . Chenery actually lost the toss, giving her the second pick of foals—it was her luck that Ogden Phipps chose the equine equivalent of Sam Bowie .

The rarest coin toss of all, and the most controversial, is one that decides the outcome of a game or a season. In 1968, a few years before the penalty shootout had taken root, Italy and the Soviet Union flipped a coin to settle a 0-0 draw in the semifinals of the European soccer championships. (Italy won the toss and the UEFA title—perhaps not a surprising outcome since the Italians hosted the tournament.) Twenty years later, Permian High—the school featured in Buzz Bissinger’s Friday Night Lights—advanced to the state football tournament via a dramatic, three-way coin flip held at a West Texas truck stop.

As the coin toss has lost its primacy in sports, sabermetricians have come to realize the outsize role luck plays in athletic endeavors. Characteristics treasured by the media and fans, like clutchness and chemistry, have been shown to be fairy tales. In baseball, newfangled stats reveal that pitchers don’t exert much control over hitters’ batting average on balls in play. Meanwhile, my colleagues at Football Outsiders deduced years ago that fumble recoveries are random .

Luck-based factors like bloop hits and fumbles and injuries and weather cannot be legislated away. As a result, the coin toss—the event that so perfectly represents fortune—gets more than its share of the blame for outcomes that are perceived to be unfair. In 2008, after the White Sox hosted the Twins in a one-game playoff on account of a flip, Chicago general manager Ken Williams told the Twins’ Bill Smith that such an outcome was “wrong and it should be changed.” A few months later, Major League Baseball complied—home-field advantage in one-game playoffs is now “ determined by a set of performance-based criteria that will begin with the head-to-head record between the tied clubs.”

While the flip has been excised from the national pastime, the gridiron has yet to rid itself of the cursed toss. The most notable alternative to football’s opening coin flip—the XFL’s Braveheart-style Scramble —proved as successful as Linda McMahon’s Senate campaign. (And given the growing concern over head injuries, the Scramble seems unlikely to make a comeback.) The NFL still lists the coin flip as its final playoff tiebreaker , after such obscure stats as net touchdowns in all games. And New York Jets owner Woody Johnson recently blew a gasket when a coin granted the Giants the privilege of the first home game in the New Meadowlands.

So get in the spirit while watching the NFL on Thursday: Call heads or tails with your father-in-law for that last piece of pumpkin pie. Just don’t flip a coin to determine whether the TV stays on during dinner. In all realms of life, there are some decisions that are just too important to leave up to the fates.

Like Slate on Facebook. Follow us on Twitter.