Eternal love is actually not like human emotions. Human emotions cannot be changed. Of course, we pursue eternal love (this is two concepts).
In my opinion, the most human-like time for David was when he found out that he was not the only one and then went crazy and destroyed the same robot as him. It could be counted as suicide if he really didn't want to live at that time. As for his tears, I want to say that he has no human physiological structure. Tears are too fairy tale to be real. If he has a structure that simulates tears (like the sex robot said, the body temperature rises during sex), but tears have nothing to do with human nature. Well, he's only human when he's emotionally driven (whether in tears or not).
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