Principle number 13 of Basic Elements of Islam: You must pray five times a day. This is one of the five "pillars" — that is, one of the five central practices — of Islam. Within an Islamic state, this practice is enforced by law. Every Muslim must pray five times a day. The practice helps Islam dominate a Muslim's life, filling his daily rhythm with Islam.
It would be impossible to forget anything you deliberately do so often. Five times a day, every day, a Muslim must bow down and pray to Allah.
Research has shown that the more effort a person expends for a cause, the more he is likely to believe in it and value it. So this is a good way to eventually make believers out of people who became Muslims through coercion.
Islam completely takes over every aspect of Muslims' lives. Not only are they required to pray five times a day, they have to go through a washing ritual beforehand. Islam dictates the laws, and the laws cover many public and private behaviors. In an Islamic state, it is impossible to be a casual Muslim.