Вот людям, у которых английский так себе, не рекомендуется рассказывать другим что у них поехала крыша.

http://en.wikipedia.org/wiki/Double_negative
A double negative occurs when two forms of negation are used in the same sentence.
...
In standard written English, when two negatives are used in one sentence, the negatives are understood to cancel one another and produce a weakened affirmative. However, in many dialects, the second negative is employed as an intensifier and should be understood as strengthening the negation rather than removing it.

In the film Mary Poppins, the chimney sweep Bert employs a double negative when he says, "If you don't want to go nowhere..." Another is used by the bandits in the "Stinking Badges" scene of John Huston's The Treasure of the Sierra Madre: "Badges? We ain't got no badges. We don't need no badges!" More recently,[when?] the British television show EastEnders has received some publicity over the Estuary accent of character Dot Branning, who speaks with double and triple negatives ("I ain't never heard of no license.").[citation needed]

In music, double negatives can be employed to similar effect (as in Pink Floyd's "Another Brick in the Wall", in which schoolchildren chant "We don't need no education / We don't need no thought control") or used to establish a frank and informal tone (as in The Rolling Stones' "(I Can't Get No) Satisfaction.").

Совершенно верно. Мы санитары леса, не даем интернету окончательно отупеть. Ну если так - то народ, в моем лице, примотрелся и сделал правильное заключение, что крыша поехала именно у тебя.
Так лучше ? Человеку, не знающему про "we don't need no education" не стоит даже заикаться об английской грамматике.