Princess MoMo’s bladder required relief. She moseyed to the restroom in the drinking establishment. After waiting in the inevitable line, MoMo entered the stall. She sat her royal ass upon the toilet throne. In the stall next to MoMo, an individual was loudly describing her distaste for another female to her friend. One of her statements was, “I don’t give a fuck where she lives at.” MoMo’s ears cringed. Being the grammatical giver that she is, MoMo let her voice be heard. She said from within the commode cubicle, “Can I tell you something? You cannot end a sentence in a preposition that way.”[1]
[1] MoMo is not a stickler on the “don’t end your sentence in a preposition” rule, but this was a particularly egregious grammatical error because the “at” didn’t even appropriately belong in the sentence, regardless of its position therein. (You may be thinking, “What a hypocrite this MoMo is. She just ended the sentence in a preposition (therein).” But no, that thought is wrong. “Therein” is an adverb in that sentence.)
Well, actually, you can end a sentence with a preposition so long as the meaning is understood by the context of the sentence, and as long as said meaning isn’t redundant. Yes, in this case, your tinkle partner used it improperly (because of the redundancy in her statement), but not because she ended it with a preposition. The rules are not the same anymore, and most English scholars feel that phrasing a sentence to not end with a preposition makes it sound stilted. An analog to this would be having a double space after a full stop. Just sayin’. :-)