What's the most brutal insult you can think of?

Not eating my granny's banana bread she made from scratch.

I think any insult that attacks the person's very existence is the worst..Like saying "I wish you were never born" or things that mean the same type of thing... "The world would've been better off without you" etc...

Wow, you and our current president could be brothers

I shit upon the grave of your father
In cultures where ancestors are so important, that's just about as low as it gets

You look like when you were a baby your mom had to tie you on a string so the cat would play with you because nobody else would.

Your father should've gone for a blow job instead

Your father should have settled for a blow job the night you were conceived

You have more dick in your personality than you do in your pants

A hamster has more sense than you.

You have questionable character.

Being called a lier.

"If I could [b]buy[/b] you for what I think you're worth and [b]sell[/b] you for what [b]you[/b] think you're worth, I'd be rich..."