"Yes, everybody's happy now." pg. 75This quote reiterates the conditioning each person undergoes in World State. The controllers program each "class" to appreciate their own particular ranking in society. Each class, no matter how high or low they are ranked, are perfectly content where they stand. The reasoning behind this is perhaps to avoid social rebellion. If the lower ranked classes are conditioned to be happy with their placement, they have no reason to revolt. This just enforces the power the controller has over each human being. I think that this power is symbolized by the "drug" soma. When the people take soma, they are reminded of the social structure of the World State and are more freely promiscuous and willing to be with others, which is highly accepted in this society.
This quote is also rather misleading. Bernard, who would be included in everybody, is not happy. He is still an outcast and can not seem to accept the structure of society. He does his best to fit in by participating in his Solidarity Service and then lying about how fulfilling of an experience it was. Instead of being wonderful, Bernard felt more isolated and separated than ever before. Its as if the void between Bernard and the others is continually growing more and more, leaving Bernard to be more frustrated by the social customs of the World State.