Confirmation Bias

Confirmation Bias or Tunnel Vision is when a player becomes convinced by their own arguments by virtue of how long or how strong they hold them. It is a form of Logical Fallacy, much like Appeal to Probability but applying to the person who makes the argument, not their audience.

It is not always a false assumption, but it can be blinding to new or better options that come along, because they do not match the player's "pet theory".