People around here say things are “up under” other things.
Where’s the remote? Up under the sofa!
Why do we take a dump. It should be, “I am going to leave a dump.”
SFC Schwartz
My understanding is that the correct phrase IS “I couldn’t care less” but it managed to morph into “I could care less” and since most people say things without really paying attention to them as long as they convey the correct meaning (see: this thread) it tends not to get corrected.
I think apes can seem to act “crazy” – sort of like humans do when they are feeling violently angry – jump up and down and scream and randomly throw things. Shit is probably an intensifier in this context – just means ‘worse, more so, more shocking’.
The same would be true of batshit crazy. Deriving initially from ‘he has bats in his belfry’ meaning that up in his head (analogous to the topmost part of a church, where the bells are), its just chittering and flapping. “he’s bats” is a shortening of the whole phrase, and then the crazy and the shit part get added later.
Just my amateur opinion . . .
Except for onomatopoeia, all language consists of arbitrary sounds indexed to things, ideas and grammatical relationships. There’s no particular reason why the sound /tɜrn/ should signify anything at all, let alone what the OP thinks it should signify. Same thing with the sound /aʊt/. Just because they’re put together doesn’t mean suddenly the inherent arbitrariness of language should disappear.
So it’s strange that the OP wants to demand that a phrasal verb should be the place where the arbitrariness of language stops. Phrasal verbs are one of the least “governed” area of English semantics. Let’s start with something more basic, like /mɑmɑ/.
Parking in a drive way and driving on a park way.
Old army joke: why do privates eat in the general mess and generals eat in a private mess?
“And how this amazing product works? You see”…
“You see”???
No I can’t mister radio announcer, you are on the radio. 
Normally I do not rely on Urbandictionary but this entry makes sense, not a definitive answer though:
Metamorphosis means for an insect to change, so now people have shortened it to “morph”. They chose the wrong part of the word- “meta” means change, not “morph”.
“Could care less.”
I know what many people mean is “**Couldn’t ** care less.” But they often end up saying it wrong.
“Put on your shoes and socks.”
Wait a minute, in that order?
OK, that does make sense. Thanks.
Seldom’s pet peeve…“It’ll get worse before it gets better” Say what?? how do you know?
(And it just occurred to me…“pet peeve” doesn’t make a whole lot of sense either)
I also hate the word ‘extraordinary’. It makes it sound like something is extra-ordinary. You know. Not just plain, but REALLY plain.
Interesting. I always thought it was just chimps that did that.
OK, two more then.
One, half assed. What does your ass have to do with how much effort you put into something? Oh, and I already looked at Urban dictionary first before posting this, so :p.
Two, laughing your ass off. Uhm, it’s your head that does the laughing, so laughing your head off makes sense.
Sure it does. Pet means favorite, so “my favorite thing that pisses me off”
Yeah, it does sound like that - but it does make sense though, it’s from the Latin: extra ordinem, out of the usual order. Outside the ordinary.
Oh, yeah, “half-assed”. Whoever coined that one obviously didn’t know very many mules-- They never do anything in a half-assed way.
Another example of something that started out logical (“heels over head”), got misused a few centuries ago, and the “wrong” version took over. I have no idea why.
In my humble opinion, using the phrase “I could care less” is a sign of sloppy thinking and sloppy speaking. It’s just plain flat-out wrong.
Okay, descriptivists, is the target on my back big enough now? 
This one makes plenty of sense.
A driveway was originally the place where you drove between the road and the garage (or the road and the carriage house, or the road and the courtyard, or whatever). It was, indeed, intended to be driven upon.
A parkway was originally a road in a park-like setting, with trees and plants and stuff. The word “park” in the name had nothing to do with parking cars.