How appropriate, you fight like a cow.
I always thought it was funny how often "suck my dick" was used as in insult considering what the actual outcome would be if the person you were insulting decided to actually slob on your knob. It carries the biggest unidirectionally implied gayness of all insults and to top it off, it would mean having someone you just insulted putting their sharp teeth on your weiner.
For that reason, I say "suck my dick" is the funniest insult.
Close runners up:
Any Beavis and Butthead insult (fartknocker, dillweed, etc.)
"May the fleas of a thousand camels infest your armpits."
Anything that turns a perfectly innocent comment into a reason to insult someone (ex: "Aww man, it's raining." resp. "I don't mind the rain, it's fuckers that talk about the weather that REALLY piss me off.")
ALL the original Monkey Island insults (Google it)
