“You genius” sounds like a compliment to me. A “funny” compliment. Would it be taken as sarcasm in the US? It really depends the tone I guess but in Australian english I wouldnt interpret it as sarcasm.
I think that changing it to something gramatically correct would make it into a compliment. "You are a genius" would make it positively charged. However, I would expect "you genius" to be something that, for instance, someone would exclaim when someone cuts their hand when trying to open an avocado. Meanwhile I think it would be strange to exclaim "you genius" when someone solves a partial differential equation. But it probably does rely on the tone.
Well the prequels were supposed to be more of a condemnation of the original Jedi order. The Jedi were supposed to be these hypocritical religious zealots and Anakin was supposed to be drawn to the darkside because of that hypocrisy. It's why he was "too old" to train because they wanted tiny minds to indoctrinate.
All of this culminates into that penultimate line by Obi-Wan. It's illustrating that hypocrisy.
However Lucas has the directing chops and subtlety of cocaine bear and this all went flat. You see this more watching deleted scenes and reading some of the side content.
This has been a Brit thing for a decade or so, particularly Scots and Northern English. The idea is to use a noun that could already be a slightly insulting word to start with, like 'potato' in the example
Almost any adjective works. It's the 'you' part that implies ire and intended denigration.
You incredible sock!
You blind carrot!
You empty bottle!
You missing tooth!
You complete thumb!
You glazed pie!
You stewed milk!
You wet sandwich!
You frosted toenail!
You waxy discharge!
You nauseous chifferobe!
Okay maybe not every one of them works but I think most of the time you can just put on a bad attitude and attach a adjective to an object to create some rare insults.
I think it works best with an adjective that has 3+ syllables. E.g.
You incorrigible turnip
You reprehensible teapot
You abominable spoon
You acephalous sandwich
I've watched all of the Gordon Ramsey Kitchen Nightmares series and it's full of these, except it's usually fuckin' instead of absolute.
My favorite is when after having lunch he went back to the kitchen to find they were just microwaving everything. The exchange went something like this:
"Did I have anything for lunch that wasn't microwaved?"
"your salad"
"Of course you don't microwave a salad you fuckin' donut"