Feng Shui is not a religion and is not anti-religious as Feng Shui is not faith based but science based. Not based on mysticism or intuition. Although Feng Shui seems to have a history of being mysterious as Feng Shui was not allowed by commoners and was kept secret by Emperors to maintain control.
Feng Shui not only applies to houses, but all buildings and relates to all energy as it is applied to cities, countries and the world as well as people.
Mirrors do not attract energy as thought in superstitious forms of Feng Shui. As mirrors are very shiny they reflect light and cause disturbing Qi, which is not beneficial to people. Centuries ago, when Feng Shui masters recommended the use of a mirror in certain areas, mirrors in those days were made of highly polished metal. The remedy required was heavy metal to slow down energy that caused disturbances and mirrors today have very little metal to speak of.
Reading several books on Feng Shui can be very confusing as the two methods of Western Feng Shui are conflicting. These methods called Black Hat and 8-house Feng Shui may be considered to be fast food or self medicating. Traditional Feng Shui has been around for over 4,000 years, whereas Black Hat Feng Shui was developed for the westerner less than 20 years ago and most of the books are based on this system. This method is not Feng Shui and depends on the power of the mind, which in itself is amazing. However most people find that the results it brings do not last long, about as long as you can keep a positive mind for. The 8-house or Ba Gua method of Feng Shui is practiced by Lillian Too and is essentially a compass school system of Feng Shui based on Traditional Chinese Feng Shui, however this method used by westerners is only half of the system and relies on superstitious artifacts such as 3-legged toads and taps into the power of the positive mind.
Feng Shui is much more than moving furniture and clutter, although it is important to have a space for a good flow of energy throughout the building.