I called my ex girlfriend a bitch. She got offended. Bitch is a classic insult. It has been around and used for years. Simple direct and to the point.
A plague o' both your houses! Henry V. I'll be no longer guilty of this sin; this sanguine coward, this bed-presser, this horseback-breaker, this huge hill of flesh,— Falstaff. 'Sblood, you starveling, you elf-skin, you dried neat's tongue, you bull's pizzle, you stock-fish! O for breath to utter what is like thee! you tailor's-yard, you sheath, you bowcase; you vile standing-tuck,—