Americans are often derided for not liking soccer because it is low-scoring. They are accused of not being able to understand that a sport that does not have much scoring can be exciting. They are also accused of not being able to accept ties. While there are some people who think soccer is boring because it is low-scoring, there are others who think it is boring simply because of its nature. I personally am a fan of the sport and am especially a fan of the World Cup. (Aside: I appreciate FIFA scheduling the World Cup to coincide with the worst three years for the Cubs in the last decade: 2002, 2006 & 2010).
However, the supporters of soccer should realize that there is a fundamental problem with soccer that is related to its low-scoring: the importance of questionable refereeing decisions. If a goal is rare a flawed referee call wiping out or failing to wipe out a goal is going to be much more important than in a referee call incorrectly waving-off a basket in basketball. This World Cup there have been four key goal/no goal calls that I remember:
England vs. Germany
Argentina vs. Mexico
US vs. Slovenia
US vs. Algeria
Three of these were early in the game (all but the US vs. Slovenia) and all but one was considered to make the difference in the outcome (the US scored late against to Algeria to make the earlier missed goal meaningless). *
In other sports what are the key referee decisions which are remembered, whether they were correct or not, were all late in the game:
These were all 50-50 games that ended up being influenced by a referee decision but got to that point in the game by being evenly matched. Some soccer calls are so influential that they end up completely dictating the outcome.
* There have been some questionable Red Cards as well and the controversy over the Suarez hand ball. However, the Suarez hand ball was almost universally seen as the correct call with the rule coming under fire, and Red Cards are more subjective than other decisions.