Brian Phillips gives one of the best descriptions of soccer you'll ever read. . .
There are two reasons, basically, why soccer lends itself to spectatorial boredom. One is that the game is mercilessly hard to play at a high level. (You know, what with the whole "maneuver a small ball via precisely coordinated spontaneous group movement with 10 other people on a huge field while 11 guys try to knock it away from you, and oh, by the way, you can't use your arms and hands" element.) The other is that the gameplay almost never stops — it's a near-continuous flow for 45-plus minutes at a stretch, with only very occasional resets. Combine those two factors and you have a game that's uniquely adapted for long periods of play where, say, the first team's winger goes airborne to bring down a goal kick, but he jumps a little too soon, so the ball kind of kachunks off one side of his face, then the second team's fullback gets control of it, and he sees his attacking midfielder lurking unmarked in the center of the pitch, so he kludges the ball 20 yards upfield, but by the time it gets there the first team's holding midfielder has already closed him down and gone in for a rough tackle, and while the first team's attacking midfielder is rolling around on the ground the second team's right back runs onto the loose ball, only he's being harassed by two defenders, so he tries to knock it ahead and slip through them, but one of them gets a foot to it, so the ball sproings up in the air … etc., etc., etc. Both teams have carefully worked-out tactical plans that influence everything they're trying to do. But the gameplay is so relentless that it can't help but go through these periodic bouts of semi-decomposition.
But — and here's the obvious answer to the "Why are we doing this?" question — those same two qualities, difficulty and fluidity, also mean that soccer is uniquely adapted to produce moments of awesome visual beauty. Variables converge. Players discover solutions to problems it would be impossible to summarize without math. . . . In sports, pure chaos is boring. Soccer gives players more chaos to contend with than any other major sport. So there's something uniquely thrilling about the moments when they manage to impose their own order on it.
Phillips notes that the Big 3 of American team sports have rules that limit the amount of chaos players have to contend with ("baseball constantly resets to the same starting position, football does the same while adding 29,384 rules about who can and can't do what on which plays, basketball breaks itself into discrete timed segments, etc."). I'm a fan of all three -- and all three have their own unique charms and potential to amaze -- but speaking as a fairly recent soccer-loving convert those sports don't get inside your head like soccer does. Which is why the only football I'll be sitting down to watch this weekend is played on a pitch with a spherical ball. Bring on the boredom!