People observe different things and even then, weight the memories of those observations differently. There are many who employ a barrage of "factual" observations. These are unavoidably biased even as the speaker attempts to pan the feelings out.

Often a speaker doing this feels that the sheer number of data points makes their strategy (that they will argue for shortly after finishing their list of observations) all but inevitable. People who have interacted with such arguers get understandably defensive when shown a barrage of facts painting them a certain way.

In the presence of a pattern of behavior, one example followed by every means necessary of keeping the offender on your side while building a strategy should be enough if the pattern is real and the offender has good intentions.