Lwaxana Troi
I know everyone generally hates Lwaxana Troi but beyond being the mother from hell ( Majel Barrett-Roddenberry's words) what else makes you dislike her. For me it's the importance and arrogance she places on the following " Daughter of the 5th House, Holder of the Sacred Chalice of Rixx. Heir to the Holy Rings of Betazed" yet we never find out what exactly that means. Nor do we find out anything about Betazoid culture beyond they get married naked.