Disclaimer: I'm American. I like baseball, hockey, and football (not what the rest of the world calls "football" but what the U.S. calls "football"). Here's a sketch highlighting the differences.
Most Americans mention diving, whining, and scoreless ties when they attack soccer, but these are only symptoms of what aggravates me. I create systems for a living (computer systems). As a result, I tend to see things as systems (sets of rules), and I'm ultra-sensitive when I perceive a systemic flaw but see no hope for change.
Like soccer, these sports are meant to highlight competition between two teams, so rules are put into place to keep the competition fair and declare a winner. When the games highlight the fallibility of the officials or the rules themselves, the sport must adapt, not just blame the refs and continue on.
Soccer players run roughly 10 miles (16 Km) a game while primarily using their feet to move or steal the ball. It's no surprise soccer players fall down so much: they're exhausted, and the focus is on where their balance is most easily disturbed.
Making the exhaustion worse, each team is allowed merely three substitutions per game. Did your opponent just kick you in the face breaking your nose? Use one of your three substitutions or play a man down while you stop the bleeding and set the fracture. Regular substitutions would allow the players time to catch their breathe, recover, and stay on their feet more often. Now the only real break players get is halftime and convincing the referees to stop play: the diving problem.
The rules of soccer defer many decisions to the referee's judgement: most importantly was that fall simulated, incidental, or dangerous? The referee's judgement can vary widely over the course of a game, so players do their best to influence the call: exaggerating falls, fabricating injuries, whining, and arguing.
The referees may card for diving, which I've personally never seen, but most likely the worst outcome is being ignored or getting a chance to catch your breathe. On the positive side, you may get a free kick, penalty kick, or a man-advantage: a huge swing in the game.
Can the ref really see what each player's feet were doing in realtime? Reviews of game-changing calls wouldn't slow the game down any more than the exaggerated falls and injuries already do. Maybe getting the call right more often would encourage the players to produce more scoring opportunities for themselves instead looking towards the refs to do it for them.
Most sports have scoring opportunities at every turn: any football snap could be a touchdown, any pitch could be a home run, and hockey players are rarely more than one good pass from the opposing net. In contrast, soccer seems to take three or more great touches to create an opportunity and only one rather standard play to disrupt it. Soccer is a low scoring game but that doesn't mean it's inherently boring.
If a team has little incentive to win (versus tie), is playing a man down, or is simply over-matched, they drop into a defense-first strategy and hope for a lucky break in the offensive half, possibly provided by the referee. This is when soccer lacks scoring opportunities and thus becomes boring.
Soccer is quite fun to watch when both teams are trying their hardest to score and the referees aren't blowing calls, but in the World Cup this seems limited to the beginning of matches, then one or both teams digress into risk-adverse play. They are fine with the current score and just want to keep the other team from scoring.
One play often determines the positive or negative outcome. Mistakes become exponential, and risk becomes too risky. Andrés Escobar's own goal may have been a contributing factor in his murder ten days later. Robert Green failed to stop an easy shot on goal and "may never be forgiven". Both these plays occurred in the first half, but because a defense-first strategy is easier to achieve in soccer, the team could not redeem their teammate, and he became the goat. No one wants to be the goat, so players stop taking risks. The game becomes full of smart, safe plays and thus is boring.
Soccer is aggravating but not aggravating like the Denver Broncos losing the Super Bowl 43-8, or the Atlanta Braves and San Jose Sharks consistently losing in the postseason. Those are team failures. Soccer is aggravating because it does nothing to prevent players from falling, nothing to push teams into more balanced offensive/defensive strategies, and nothing to help the referees call a good game: systemic failures.
Listen to how Steve Young addressed the controversy during the NFL replacement refereeing disaster. He didn't attack the referees. He attacked the establishment, the system, the NFL: "they don't care". I want to hear this type of discussion for soccer when an egregious error determines the outcome of a match, not just hear about FIFA sending referees home.
Ultimately, soccer's success prevents it from changing. The NFL, MLB, and NHL are dictatorships: change is swift and heavy-handed. FIFA is an enormous federation, appeasing countless countries, languages, and people. I imagine regional soccer leagues do more to curtail systemic issues but that's irrelevant as long as the World Cup remains soccer's flagship way of introducing and promoting the sport.
Let me repeat, soccer is fun to watch when both teams are trying their hardest to score and the referees aren't blowing calls, which seems to be rare. So every four years I'll watch in bars full of drunken "U-S-A" chants, waiting to celebrate a goal with everyone, while hoping I'm too tipsy or distracted to fume at the inconsistent whistles, the five defenders in the box, the non-stop whining at the referees, and the game-determining blown calls.