Let's Get Shakespearean
My favorite Shakespearean insult is - "Could you ask your mother to stop barking? It is keeping me awake."
Honourable mentions include "would you were clean enough to spit upon!"; "Come out you sheep lovers!"; "If you spend word for word with me, i shall make your wit bankrupt."; "Thou hath not so much brain, as ear wax."; "Thou wilt fall backwards when thou hast more wit"
And finally, "Come thou tedious fool. To the purpose."
This sounds like something Snape would say
There was this incredibly snotty kid I went to high school with. He was bright, but not exceptionally bright. His parents were wealthy and he was good enough to qualify for AP classes so he felt special. He couldn't help but let everyone else know how special he was... Our AP history teacher told him that he would "see how painfully average" he was when he got to college. It was great.
The lyrical burn
Adapted from Bob Dylan's "Positively 4th Street",
I wish that for a moment you could stand in my shoes, then you'd know what a drag it is to see you