> use in a way you don't expect to gain control of things you do care about

An example would really drive your point home. Can you provide one that people would deem "dangerous"?

Edit: ccooffee just mentioned in the thread that you could be de-anonymized by reusing the same password. Is this what you mean? There's a spectrum of comfort with privacy so maybe that's the source of the disagreement between whether it is important to have unique passwords or not for accounts that don't contain financial/SSN/medical/etc information