An insecure person that is so emotionally unstable and needy, that they have to constantly be coddled and be the center of attention in any given situation. Or a person that is so insecure about their own intelligence and the above average intelligence of everyone in the room, that they constantly need to talk out of their ass about stupid random things that nobody cares about, constantly giving little factoids about the same subject(and the only one they know about) over and over and over and over again, as well as speaking in an overwhelmingly loud voice to overpower anyone else that cares to get a word in. All while being hilariously unaware that everyone in the room takes a deep sigh and rolls their eyes when this person starts to speak.
Even though 29 year old Sarina, who had a rocky relationship lasting about a year and change with her f-buddy turned boyfriend of about 5 years younger, and had just mentioned several times within the past month about leaving him, was an attention whore, so she couldn't handle the fact that her younger sister of 7 years (who everyone seemed to adore because she was lovable, cute and quirky as opposed to an icy bitch that steamrolled anyone who got in her way, among other major personality disorders) had just announced an engagement to her live-in boyfriend of over 3 years, so she did the only thing she could do to make herself feel better and grab the limelight for herself-- she announced 2 weeks after her younger sister got engaged that she too was getting engaged and would be getting married about 1 month before her younger sister in pretty much the same exact fashion as her sister's wedding. This coming out of nowhere and without a ring even, which she chalked up to being something minimal that wasn't needed (she later got one about 1.5 months later when she had the money). Then, later, after several months of hell for the younger sister who was pressured from all angles to join Sarina in a double wedding day reception (to apparently support her financially because she couldn't afford everything herself) that goes against everything that her younger sister and her fiancé wanted for themselves, the wedding goes down and Sarina of course plays the control freak at every situation, not letting her younger sister have any say in any matters, as she steamrolls her at every disagreement, all while carefully making sure that she-- not her sister, was at the very center of any attention throughout the months leading up, and during the day of the wedding.
Other characteristics include “raging bitch disorder”, excessive crying over petty meaningless crap (and then denying that you ever cry, when everyone knows you do it at least a couple times a week in public), waving and slamming papers in other people’s faces, talking really LOUD, making sure that everyone hears your voice over everyone else in the room, and being very defensive and taking things personal and wrong in almost every situation. Basically just acting like a moronic emotional powder keg in every situation, and being completely oblivious to the fact that most people that know you are whispering things behind your back.