A recent survey in the Netherlands investigated what are the big taboos in Dutch culture. Following up on that, De Standaard surveyed what are the big taboos in Flemish culture.
What I found interesting are the taboos rounding the top ten list:
9. Believing in Jesus
It is not so easy to be a believing Christian. Rik Torfs, professor of church law: "For a long time we've lived under the whip of the church and now that we are freed of the church institute, we also freed ourselves from the faith. Even so terrible that you don't dare anymore to admit that you still believe. I am often asked: 'How can it be that an intelligent man is religious?' Also believing in the resurrection of Jesus is a taboo."
10. Not believing in Allah
In Christianity believing is a taboo, but in Islam the taboo is not to believe. Philosoph Tarek Fraihi: "It is difficult as a Muslim to say to the Muslim community that you believe in the cultural aspects of Islam but not in the religious. I believe in the values of Islam, but not in prayer. Saying that you don't take part in Ramadan and therefore eat, is a taboo in the Muslim community."
Source: De Standaard (Dutch)