My sister has a cluster inside the 8th house. She sees through people, she really sees them as they are. She likes more reserved people, not comfortable with nicey-nice attitude when there is someone she doesn't know.
I feel uncomfortable with nicey-nice people too - same as my sister, when they are people I first encounter. They make me feel suspicious and I have the need to keep distance and observe them... I just feel the need to be precacious. I have Pluto n the 1st house and aspecting my Ascedant, if it counts 
If these people are like this, and in tme I notice is part of who they are and how they act, it's ok to me their nicey-niceness
Don't know if I'm an 8th house person. I've Saturn and Pluto in 8th. If I sense they are being insincere or superficial then I don't like it.
My partner has 8th SN in Virgo and hates nicey-niceness. In fact, he abhorrs it. I only have Lilith in Libra in the 8th, but it does help me uncover those people using their own weapons. My 9th house Scorpio Moon and Pluto feel uncomfortable with their demeanor and my MC in Scorpio shows my dedication to this.
I have a packed 8th but I also have Libra and don't mind the nicey-nice. I even appreciate them.
This changes when a person like that stabs me (or anyone) in the back. But I do think there are very nice people out there. I think they opt to be that way, perhaps because they were trained but some of them have just realized it's easier to get through life... catch more flies with honey?
I know people think people in the south are "fake nice" and some are. But a lot them are truly nice. They've been that way all their life and don't know any other way to be, nor see a need to change.
When I first moved here, some gal in a store told me that all I needed to do to fare well in the area is to be nice. That's a heck of a statement, really. I've found it to be true.
Around here, being nice is a way to have tremendous freedom. You can do anything but act an ass!
The ruler of my 8th is my chart ruler; depending on the house system, two planets might be there. I’m nice. Being polite was emphasized in my house, but it’s also just who I am. I’m not as nice as I used to be, simply because I realized I pay better attention when I’m more reserved.
What annoys me more than nicey-nice people, is people who “tell it like it is” when they are not only full of it, but getting off on being mean. It’s seems common for people to doubt niceness, because of its connection to social niceties but way too many people mistake meanness for sincerity. Usually, all I see is hurt and scared person wreaking havoc.