A common rhetorical technique I see being used all the time is to make arguments based on isolated statements.
The formula is: “Because Person X said Y, she is or isn’t Z.”
The issue with this approach is that ignores the fact that context reveals unspoken principles.
If you meet a person who extols the value of disruptive protests, but only ever cites examples from one side of the political spectrum, the broader pattern of his or her statements provides more valuable information than the actual words themselves.
Similarly, a person who has demonstrated a history of valuing facts and being willing to consider alternate points of view is more likely to be credible when presenting an argument with which you currently disagree.
What are the unspoken principles that you are communicating with what you choose not to say?