I gotta say, I've had experience with people (U-Verse, for one) who come to my door and won't take no for an answer.
![rolleyes rolleyes](/threads/images/graemlins/classic/rolleyes.gif)
I literally have to close the door while their still talking in order for them to understand I'm not interested.
I seldom used to answer the door (people who know me would just come on in), but then I adopted a full grown, noisy German Shepherd. He's a cream puff and the world's friend, but sales people don't know that, and most last less then 30 seconds in the face of his barking.