Called out by a kind, frank friend: the personal tendency to assume during conversation that a listener is just like oneself — e.g., knows about switch-contact bounce and how to diagonalize a matrix, loves to run on strange new trails to unknown destinations before dawn, strives for self-awareness and non-attachment, etc.
In response to the 2011 Edge.org challenge question, "What Scientific Concept Would Improve Everybody's Cognitive Toolkit?", neuroscientist Christian Keysers nominates what he calls the "Mirror Fallacy": the notion that other people feel and think just the way we would in their circumstances.
(see Wikipedia's Projection Bias, Cognitive Traps for Intelligence Analysis and List of Cognitive Biases; cf. Big Biases (2014-01-09), Negative Thinking Patterns (2015-08-28), ...) - ^z - 2016-03-10