It's played by more people than any other sport, watched by more people than any other sport, followed more fervently than any other sport, and all this across more countries than any other sport. What's football's magic, what's it got that no other sport's got and how does it somehow trump all others?
It might not be your favourite sport but that's not relevant here - on a global stage football dominates all.
One reason is that football's so simple to play. It's just you and a ball and all you have to do is kick it. Most other sports are much faffier, requiring specialist equipment like a net, a hoop, a hole or something special to hold or wear. Football merely requires a ball, and not even necessarily a special ball - you can play a decent game with spheres of various types and sizes so long as they're suitably bouncy.
Another reason is you can play it almost anywhere. Ideally you need a big rectangle of grass but fake grass will do, even something more solid potentially indoors, And the rectangle doesn't have to be a specific size, a reasonable range applies, and if playing unofficially you can shrink that down considerably. Even if all you have is the corner of a playground you can still use jumpers for goalposts or chalk on a wall. It scales up, it scales down.
Another reason is it's dead simple to understand. Each team tries to kick the ball between the other team's goalposts and the team that does this most often wins. Obviously there are other rules, indeed one of these is the offside rule which is notoriously difficult to unpick, but the underlying 'count the goals' rule is brilliantly simple. Compare this with tennis (deuce, advantage, game, set, match) or even, heaven forbid, American football.
Another reason is you can imagine you might be good at it. It's only kicking a ball with your foot, how difficult can it be? Extremely difficult as it turns out, at least at the highest levels, but the fundamental basics are within any able-bodied player's reach. This is also why millions of children dream of being a professional footballer, however misguided the aspiration, because why shouldn't the next Harry Kane be them?
Another reason is the element of surprise. The better team usually wins but not always, the chance of an upset is always there and happens just often enough to give everyone hope. Also the games themselves often bring surprising moves, indeed it's pretty much impossible to predict what the field of play will look like in a minute's time (whereas in tennis, say, you know it'll still look like two people either side of a net).
Another is that it creates heroes and villains. One great goal can be talked about forever, whereas one penalty missed can put you in a nation's bad books with no hope of reprieve. Also that glory/infamy can either be at player level or team level, thereby multiplying the fascination, and sometimes what looks like the worst drubbing in the world can all be forgotten by next weekend.
Another reason is it's a common language. I was in the library the other day and three people who'd never normally have spoken were engaged in an animated in-depth conversation about the last match and the next - absolutely invested - which they'd never have done were the topic cricket, politics, climate change, whatever. Not everyone has a footballing point of view, granted, but in no other field is so much expertise shared by so many.
Another reason is the hierarchy of competition. Whatever level your team's at they could always be doing better, or worryingly doing worse, so there's always a narrative drive going forward. Do well in this competition and we'll let you play in the next tier, right up to the full-on continental pinnacle, and even if you win that the next step is to try to do it consecutively because the pressure never ever eases up.
Another reason is nostalgia. Football's been going so long that every team has a lovingly-tended backstory. Even if you're not doing great right now there's always that time when you were, be it an entire season, a glorious cup run or a distant tournament's quarter final. Memories of a giant-killing goal on a Tuesday evening 30 years ago have sustained many a supporter through another turgid run of draws and defeats.
Another reason is that it's tribal. Everyone has a favourite team, even those who barely follow the game, even if that team is their default local side or national squad. For those who follow more faithfully football becomes something of a religion, arguably more of a belief system than religion itself, a blind all-consuming devotion to be carried to the grave. You just don't get that in Formula 1, baseball or darts.
Another reason is the embodiment of nationalism in sport. The England flag and the England team run hand in hand, at least in the minds of many, as if the performance of eleven players somehow embodies the soul of the country. And it's the same elsewhere around the world, particularly in tournaments, where a single result can result in patriotic joy or mass collective despair (or potentially just a lot of drinking).
Another reason is the artifice of the players. Create a good pass, a well-timed tackle, a dazzling run down the wing or a magnificent shot on goal and you'll have everybody talking. Every football match is a free-flowing sequence of events any one of which can demonstrate talent and any one of which can be dissected in enormous detail later. Match of the Day would be nothing more than a highlights show were it not for the inevitable extended punditry, repeated ad nauseam in pubs around the country.
Another reason is sheer drama. Will whatever the score is now continue to the end of the match? Who'll snatch the winner, will the upcoming substitution make a difference and who was to blame for that awful tackle? In particular goals tend to become more common as a game goes on and players tire, so extra-time is always nailbiting and the showdown of a penalty shootout can be more of a coin toss than a display of talent.
Another reason is micro-management. Every fan thinks they know how they'd run the team, which players they'd pick, who they'd buy and who they'd leave on the bench. It's especially easy to have an opinion on how the current manager's doing, especially if they're doing badly, which somehow isn't so fanatically driven in other sports.
Another reason is that every match can be summed up in two numbers. If someone tells you the result was 2-1, 0-0, 4-0 or 6-6 you can instantly understand the underlying story of the game. Tennis needs lots more numbers, golf tends to go negative, cricket is a shower of digits and rugby's scoring is an artificial construct. Admittedly it's not quite as simple as a race ("Who won?), but football's number pairs are narratively all-powerful.
Another reason is the rarity of the goals. Somehow a game has evolved in which goals are relatively infrequent, generally one, two or three per half, so when one happens it's of enormous importance. If goals were ten a penny you wouldn't get that explosion of emotion when they occur, and if they were excessively infrequent there'd be far too many tedious no-score draws. I'd argue the perfectly-pitched frequency of the goals is at the very heart of what makes football shine.
Another reason, therefore, is the size of the goalposts. Any bigger and they'd let in more goals which'd cheapen things, any smaller and they'd let in fewer goals and everyone'd get bored. Kudos to the people who deduced the dimensions that worked best, and indeed how far away the penalty spot needs to be, because another few inches and it'd be a very different game.
Another reason is the sheer simplicity of the numbers. Football's not about 7s, 15s and 40s, it's about 0s, 1s, 2s and 3s. Everybody gets that. It also means there's a very limited number of likely scores, just enough to make predictions worthwhile, even if all you're going to guess is that the result'll be 2-1 because everyone predicts that.
Only two sporting events unite the planet, one being the Olympics and the other the World Cup. But the Olympics involves a multitude of sports and the World Cup just the one - the all-consuming, population-embracing sport of football. Obviously talent and tactics play their part, but it's also the simplicity of the rules, the rarity of the goals and the underlying mathematics that makes football a devotional entity.
Bear that in mind as England strives for glory tonight, or crashes and burns, and somehow an entire continent watches on.