Everyone has their own definition of normal, thus everyone must also have their own definition of goofy.
However, in the NFL the actions of the majority of the players defines what normalcy is in the league.
The players who don't follow unwritten rules while acting ridiculous and celebrating foolishly, but with great pride, deserve to be labeled goofy.
They are simply entertaining. Whether it be with their looks or their actions, they are known as the goofiest players in NFL history.