Problem:
The user wants the system to appear to be human... But not at the expense of it looking unsettling.
Anti-pattern response:
The system falls into the uncanny valley of artificial lifeform, freakishly human in many aspects but just strange enough to be sinister, eerie, or otherwise disturbing.
Discussion:
While the trope name may not be that well known, the effect is widely acknowledged, and notable examples are often subject to ridicule on social media and beyond. The lesson is that it may be better to give the UI the character of a robot, animal, or other non-human than attempt to be as human as possible. Even though the possibilities for empathy grow the more human we perceive the other party to be, it's better to hit the sweet spot with a safely abstract non-human character than risk the uncanny valley response.