Pointing a finger at someone may indeed be rude. Pointing a finger to someone is usually not rude at all.
The reason is that these imply different contexts. Pointing at someone is an aggressive gesture often indicating accusation.
The prosecutor pointed at the defendant as she addressed the jury. "Ladies and gentleman," she exclaimed, "the state will show that this is the man who committed the vile murder on the night of October 7th!"
Pointing to often merely indicates selection.
The two captains had the boys line up along the goal line. Each then took turns pointing to one of the boys to call him over onto his team.
This use can subtly change the nuance of an implied action:
"Mrs. Capshaw, can you show us the man you saw entering your neighbor's house the night of the murder?" the prosecutor asked.
Mrs. Capshaw nodded and pointed to the defendant. (selection)
Mrs. Capshaw nodded and pointed at the defendant. (accusation)
As for the answer to your question, it mostly depends on how aggressive you want to phrase your response. A simple request might be:
(Please) Don't point your finger at me.
or, alternately, you can take Canadian Yankee's suggestion of
Get your finger out of my face!
with a range of possible options in-between.
"What would you rather I do" is correct in the case where you have presented some options (or are just asking 'what to do' more generally) but are yet to take action.
"What would you rather I did [or 'had done']" would be used where you did something already, but then maybe it's being questioned so you are asking the person -- well, what should I have done instead? What would you have preferred that I did?
"What would you rather?" does get used occasionally but I think it's a bit ambiguous. If there are several options I would rephrase that to "[what/which one] would you prefer?"
Best Answer
This is grammatically correct. The ordering feels a bit off to me – I'd prefer the “are” to go at the end – but that preference feels weak enough to be just my dialect.
To answer the first question:
The simplest sentence of this form is “I wonder what it is.”. I feel like it breaks down like this, though I couldn't possibly tell you why:
jr_kim's answer, “I wonder what are your thoughts about this product” isn't incorrect per se, but it's a non-standard dialect; it's not formal, written English, and some might consider it a little odd. With different punctuation to make it a question with a preceding subordinate clause, however:
it's perfectly grammatically correct.