Pathological liars.
Immature, irresponsible, untrustworthy, and ultimately living in their own little world where details and facts are constantly spun in a way that reflects upon them positively and garners them some delicious attention. Meanwhile, if a pathological liar should be caught doing something wrong, the response is never a heartfelt apology, but rather a wild tale that ultimately serves to point the finger at a completely innocent party, solely because the pathological liar is too immature, selfish and childish to ever take responsibility for their own actions or sympathize with the fact that they're essentially trying to send an innocent party to the chopping block.
And worst of all....? This is borderline sickness; psychologists will debate if this should be named a mental disorder or merely someone who's an [censored]. Pathological liars have a different brain structure as I recall (more grey matter or whatever) and their minds have truly developed differently, perhaps out of having grown up in an environment where lies consistently led to better results and rewards. What does all this mean? Well, it means that you should be just as likely to forgive and pity them as you are to yell at and strangle them. Because sadly...? Well, I can't say I personally know of a story involving a "reformed" pathological liar. No, they're just pitiful and pathetic lost souls who'll forever live in their own little world, never realizing the only one who believes their stories is themselves. You can teach a child to take responsibility and grow up, but that doesn't seem to be the case here....
I've had the misfortune of meeting about three of these on a personal level (AKA had to associate with them daily) in the short 25 years I've been alive, and I can honestly say they send me running like no other. One of them was a preacher's daughter, funnily enough. Just thought I'd mentioned that cause as I learned she was a pathological liar, I also learned "the preacher's daughter" is notorious for having issues of some kind.
Only thing that comes close, I've encountered - very briefly - one person with histrionic personality disorder. I cannot say for certain this was the case as this was a makeshift diagnosis from a friend studying psychology and knowledgeable of the subject area, but got curious and looked it up and wow it seems like a nightmare too. In a nutshell, I encountered a pathological liar alongside the guy with histrionic personality disorder. After the pathological liar was exposed, the histrionic proceeded to....defend her, almost solely on the grounds that she was his first friend in the area. But it wasn't defending her as in "c'mon guys go easy on her," it was defending her in that he would actively go to start drama and pick fights with anyone critical of her. It was the most, illogical thing I'd ever seen, and the only explanation that seemed to fit was "he's doing it for attention and will legit do ANYTHING for attention of ANY form." So yeah, if the pathological liar wasn't bad enough, here was this idiot making it EXTRA awkward by starting fights on her behalf that she herself would never be capable of finishing (because these great things called "facts" worked against her, so he was kinda inadvertedly highlighting what a liar she was), deciding he hated perfectly reasonable and innocent people solely on the grounds that they were lied to by her. As I said, I can't say for certain it was histrionic personality disorder, but WHATEVER it was, it was so drama-prone and illogical that holy [censored] I don't wanna be anywhere close to it.