It took me about five minutes into watching my first pro wrestling match to realize that wrestling crowds are unlike any other crowds in the world.
I don't recall the exact moment of realization, but my reaction was something along the lines of "Damn. These people are vocal and organized."
These are the two common traits that run through the vast and diverse ecosystem of professional wrestling fans. They are expressive and they are precise, and the result is a stadium experience only rivaled by international soccer hooligans in their willingness and ability to express themselves en masse in no uncertain terms.