Human Nature Doesn't Change

This post is part of the Daf Yomi thread that started here.

Heard any good mother-in-law jokes recently? If not, there's an entire website of them over here.

On page 117a in Yevamot there is a Mishna dealing with some of the ways out of a situation where a husband has disappeared but it's not clear if he has died, and this of course has significant implications for his wife - or is she his widow - but also for other members of the family and potentially of a new family, if she can re-marry, or a different part of the same family, if he was childless but has brothers.

The position of this particular Mishna (about 2,000 years ago, remember) is that there are a number of women involved, first and foremost the mother-in-law, whose testimony cannot fully be trusted. The Gemara (1,700 years ago) then elaborates, and details the dynamics of the tensions - which woman hates which other woman and why. Rashi (12th century, so roughly half-way between the Mishna and us, but still 350 years before Columbus discovered the Caribbeans) tries to soften the discussion, and explains that although there are rules in these things, ultimately the individual relationship is crucial, and he brings a beautiful metaphor:
"Like calm water, when a person looks into it and sees a face like his own. If he's smiling, so is it. If he's scowling, so is it. So also is the human heart to another: if one loves, the other loves back; if one hates, the other hates back".

Sounds pretty familiar, huh? Even tho we're all modern and enlightened and far advanced compared to all those primitives?