I just find them incredibly condescending. I like to be treated like an adult, and I treat others with the same courtesy. Don't like what you're reading? Then stop reading.

All that said, I'm not going to lie. Whenever I hear warnings on television to the effect of: "The following programme contains scenes of sex, violence, bad language, disturbing material, upsetting scenes" - and this is the kicker - "from the very start", it guarantees I'll keep watching. I should bloody well hope it's from the very start too. I pay my licence fee dammit. I want my moneys worth of disturbing material. ;)