"Your mother was a hamster, and your father smelled of elder-berries!"
Usually rather than insulting people, you should just cut them off and ignore them
Found this on one of the maths forums - "You got a B in C1"
these are some of my favourites, courtesy of Adam Hill and a friend of mine:
"Insufferable prick-featured ****-smoker"
"Jaded bitter old mole"
"Mathematically inept cocksplash"
"Outdated, anachronistic, prehistoric old ****"
Suck my 4 inch penile rod peasant.
I wish I could see things from your point of view but I can't get my head that far up my arse
Your birth certificate is essentially an apology from the condom factory
Don't let your mind wander, it's a tad too small to be out by itself