They possess a deep, textbook-like and through understanding about the game of Madden and (often) football. They would rather play madden than any other video game.
Trindon Holliday is a wide receiver for the Houstan Texans who ranks in the 50's overall in Madden 11, but routinely gets open and catches passes with more consistency than some 80's or 90's. This is, once again, due to a unique combination in his attributes which makes him difficult to cover.
Wallace Gilberry is a defensive end for the Kansas City Chiefs who ranks in the 60's in Madden 11, but he has an ideal blend of speed, strength, and block shedding to consistently make tackles in the backfield, embarrassing elite offensive tackles.
These players, and many more, are Maddenites.