That someone is very unattractive and are in desperate need of someone telling them so. Usually they will be told by a chav walking past them on the street
LASHANNDRA: GIRRRRRRRRL THAT BIITCH OVER THERE IS WHINERS YA NA! WHO DOES SHE TINK SHE IS BEING UGLY ME WANN SLAP ER, I KNOW SHE WANTS MA MAAAAN
Tracey: Erm do i know you?
LASHANDRA: no sorry you dont,i just thought i would make some conversation.....so..... how was your weekend?