Well, in terms of watching, soccer and baseball are certainly the most boring sports in the world. And that is primarily because, as the fans listed here, you have to "get into it." Which basically means you have to dedicate a large amount of time trying to understand a game that is not intrinsically appealing to watch. Which seems kind of pointless.
Football, hockey, basketball, lacrosse, all of these things are intrinsically exciting. Football, because it is massive men clobbering each other, with clear objectives and an awful amount of teamwork. Hockey because of the speed, agility, toughness required (toughest game in the world), fighting, etc. Basketball because it is so clearly skilled. Lacrosse because it is usually excessively violent.
But baseball? Soccer? The only time they are exciting is during playoffs or championships, or when the fans lose their minds.