Phone sex and other things I don't get that defy logic

Sorry to tease you with such a tantalizing title and potentially disappoint, but actually, the contents of this post will not be racy because it's about logic.

There are lots of things I don't get, but here are the three that are currently on my mind.

1. Piano quintet-- when I first heard the phrase "piano quintet", many many years ago, I imagined 5 pianos clanging along. After all, a string quartet means 4 strings playing as an ensemble. So by parallel logic, shouldn't a piano quintet mean 5 pianos playing as an ensemble? Ditto guitar quintet?

And why is a trumpet quintet composed of 5 trumpets, but an oboe quintet composed of an oboe plus 4 other non-oboe instruments?

Ok, granted, I've never seen 5 oboes perform together. But I've seen an oboe duet. Maybe a trio, too? And ditto guitar. A guitar trio is an ensemble with three guitars, and the Los Angeles Guitar Quartet is composed of 4 guitar players (I think), but Boccherini's guitar quintet is for guitar plus 4 other instruments.

Is there some sort of unspoken elusive rule among musicians that they automatically know if it's x instrument, then an x quintet means x+4 other instruments, but if it's y instrument, then it means 5 of y instrument?

Or in the case of the guitar, at what number threshold, we switch from x-______tet meaning ____ of instrument x, rather than x plus other instruments?

Is there a manual that explains all of this?

2. Phone sex--ok, it's not that I didn't know what this is, but again, based on purely logical reasoning, I wasn't 100 percent sure what this meant. But Titus set me straight.

So it was what I suspected it was, but according my pedantic adherence of logic, phone sex really ought to be called phone masturbation, b/c that's what it really is. According to Titus, it's called phone sex rather than phone masturbation, because the former sounds more "exciting".

Exciting, but not logical. But then, when is sex ever logical?

3. The American convention of putting periods and commas inside quotations--this is a hobby horse of sorts for me, and regular visitors know of my befuddlement with this grammar rule, so I won't belabor the point here, except to express (again) that it's totally illogical and I refuse to abide by such rules that make no sense. (After all, what is a personal blog, if I can't express my own artistic or grammatical style, so long as I'm consistent?)

Perhaps I'm rigid like that, but all I'm asking for is consistency.
If
Did you read "encore"?
is legit, then
I read "encore".
rather than
I read "encore."
ought to be legit.

(Omg. Did I just compare piano quintets to phone sex to grammar rules??)