It annoys me because you are forcing me to decipher what you're telling me because you feel like being an annoying cunt.
Also adding "Innit" to the end of every sentence is the british version of "nowhatahmsain" for americans and "Aye" for Australians and just makes me think you are stupid.
I tried to write a joke about the Jonestown massacre once but the punchline was too long.