Offensive

I have always loved clever insults. I am sick of hearing all of the tired, old cliché snubs and am frequently, thoroughly disgusted with people who curse and swear at each other. I also really love alliteration.
If you want to express your disdain for someone and in a unique way, then I suggest some of the following slights. If you are really lucky, you may even manage to insult someone without them realizing it!
Enjoy.

You are such a(n):

Abominable, aggravating albatross
Babbling, blithering braggart
Crass, craven cretin
Diabolic, disgusting, despotic demon
Effeminate, exasperating egitt
Frenzied, fanatical fiend
Grasping, greedy gargoyle
Hellish, horrible harpy
Ignoble, ignorant, illiterate idiot
Jealous, jaded jackanapes
Kooky, kinky kleptomaniac
Lying, lascivious libertine
Malformed, malignant mongoloid
Nattering, nagging Nancy
Obnoxious, obsequious ostrich
Pompous, pretentious, probably-petite prick
Quivering, quail-hearted, querulous quack
Rabid, rancid rapscallion
Slithering, sneaky, slimy serpent
Traitorous, treacherous tramp
Unctuous, unbearable, ugly upstart
Vicious, vindictive, vainglorious viper
Wicked, wily wench
Xenophobic Xanthippe
Yellow-bellied, yammering yak
Zany, zoophagous zealot

If you want to insult someone, do it right. Be creative and quick and though they may hate you, at least they will come to respect your intellect.