Evidence that is not open to the reader of a topic, often AnecdotalEvidence. There is not a whole lot that can be done with such evidence other than AgreeToDisagree. 

Being hesitant with or skeptical of InternalEvidence is not necessarily the same as a distrust of the other person. It may be that they have not thought of an alternative solution that would be discovered if more eyes reviewed it.

Thus, neither side should take it personally. It is just the inherent nature of the beast.