You're in line at McDonald's talking to a buddy about how Burger King has better quality, is free, and that you'll not be returning to McDonald's in July because their burgers are going to cost $0.24 per microgram, and the owner is a clown.
Someone unaffiliated with McDonald's who is also standing in hears your comment and starts shouting for you to "GET OFF YOUR HIGH HORSE!"
.. not because they don't like Burger King.
.. not because they have never tried Burger King.
But because they closely identify with McDonald's, and the clown that represents it.