* CDB:
I don't know if it's much different in French, but the "Du"/"Sie"
distinction is primarily about distance, and more indirectly about
respect ("polite" tends to mix up these two aspects.)
Simplifying, of course, but to me, using "Sie" signifies either that we
have no reason to be buddies, because we have nothing in common (like
being schoolmates, colleagues, members of the same club) - I of course
used "Sie" in transient relations like meeting someone at a bus stop or
staff-customer interactions - or that we can't be buddies, because we're
in a kind of relationship that would make that awkward, e.g. teacher and
student.
One of the weirder things to me in old movies is when people flirt with
each other while still using "Sie" (though it likely happened with my
parents.) There are multiple things coming together in this:
- As mentioned, with most people (at least my age) I used "Du" from the
start anyway
- I'm more comfortable being friends before flirting seriously
- I always thought the idea silly that we can't be buddies because we're
of a different (assigned/perceived) gender
The latter is very generational. In my parents' generation, it may still
have been considered suspicious for a married person to be on a "Du"
basis with a member of the opposite sex other than your spouse. I was
maybe a bit ahead of the curve, but it should be the norm with young
people now that you can have friends of any gender. Of course in my case
there was the bit that I didn't really connect with my assigned gender.