How many assumptions have you made today?
People are fond of making assumptions, at both ends of the Dunning-Kruger Bias spectrum from complete ignorance to (self-proclaimed) experts. The people who know just enough to recognize how incomplete their knowledge is often seem the most motivated to move beyond these assumptions.
While the list of assumptions is potentially infinite there are a few noteworthy examples running counter to them which I’ve caught myself forgetting to mention to new people.