The following things invalidate the prayers: A. Urinating and releasing wind or feces. B. Turning the body fully away from the direction of the Ka'aba. C. Any act that disturbs the prayers in the view of religious people, like eating or drinking. D. Deliberate talking. E. Deliberate laughing. F. Putting one's hand on top of the other over the chest or stomach, if this is done so with the intention that it is part of the prayer. G. Deliberately saying the word "Aameen" after finishing recitation of Surah al-Fatiha. The said actions are proven by religious evidences to nullify the prayer, and we should submit to them even if we did not know the wisdom behind them.