"Nick you're being a dick." "I know you are."
This. Definitely this. All the way. Also, variables: "HEY EVERYONE NICK IS A DICK" "I'm sorry for you, it must be hard for you to be a dick." "no, u" Etc. etc. etc.
Any variation of 'nou' is an epic comeback.
That's just a matter of opinion. In my opinion it sucks, in your opinion it's epic.