To some extent, Umi and Fuu in the Rayearth TV series... sure, they both get some wonderful moments, but the amount they get tossed the idiot and/or distress ball so Hikaru can look better is astoundingly annoying. (I'd compared one friend to Umi as a compliment. The TV series made her feel it was an insult.)
Top of the annoying list includes the two of them running away from monsters so hikaru can defeat them solo, Fuu declaring 'we should draw our weapons' before they both stand there for over ten seconds so a monster can grab them and they have to be rescued, a shining moment for Umi being brought down because one of her most wonderful and character defining speeches from the manga is given to Hikaru instead (cause Hikaru has to be the centre of attention), and when she gets to make the sppeech later in a replay of the scene from the manga, Hikaru has to point out she'd said that already.
Eh, include Hikaru in that too. I loved her in the manga, but I got close to hating her in the tv series.