Here in South Carolina we have great Universities with great athletic programs. We're proud of this and many display their pride and support by wearing school colors and decorating their automobiles with tiger paws and gamecocks (in this case Clemson and The University of SC).
An avid supporter of Clemson gave a listing presentation proudly driving up in a car that looked like a billboard and wearing a tiger paw lapel pen. At the conclusion of the presentation he asked if he could work with the potential client to get their home sold. He was surprised when he was told they were going with another agent. He later saw these prospects placing groceries in their car, proudly decorated like a Gamecock billboard.
Others may have opposite opinions and will not work with you for that reason, no matter how good you are as a realtor. Displaying your passion to the public doesn't help your cause and can destroy your business!