The False-Consensus Effect is where people tend to overestimate the extent to which their opinions, beliefs, preferences, values, and habits are normal and typical of those of others (i.e., that others also think the same way that they do). This cognitive bias tends to lead to the perception of a consensus that does not exist, i.e. a “false consensus”.
One useful counter-measure is to ask yourself: How have I quantified my consensus? How many people have I asked and referenced? How valid are these samples? What other factors could be influencing my estimation?
For a full list of the most common biases, click here.