They could have histrionic personality disorder. This isn’t just attention-seeking, but goes even farther. If you know someone who has this disorder, it’s clear there’s something not right. The article I linked to could be written about my mother. It describes her behavior almost perfectly, and the lengths she will go to in order to get attention are ridiculous. She does everything from exaggerate to flat-out lie, always has drama in her life that is never due to her own bad decisions, and is a master at manipulating and using people. Her behavior ranges from deceitful and damaging to just plain funny. Being with her in public or in a group is a terrible experience.
I think what differentiates a disorder from bad habits or bad manners is crossing a certain line. If someone is lying, manipulating, or acting out with dramatic and false emotions in order to get attention and really can’t control the behavior or even consider they might have a problem, there’s a good possibility they have a disorder that could benefit from treatment.