One of the most common reasons for mothers lying to their children is to create a world of fantasy for their kids. They want to make their life magical by discussing about super-heroes, fairies, wonderlands etc. In some cases, doctors and psychologists are certainly in favor of it as it builds a sense of creativity in children while, on the other hand, lying is a bad habit and even lying about a Santa Clause or a tooth fairy needs to be avoided by the mothers.
Kids have a fragile heart and they cannot take the harsh realities of life like the elders. Therefore, in order to minimize their fears and make them feel positive towards life, mothers often opt for lying as it always helps in sugar coating the bitter truths of life.
As the innocent minds of children do not know much about the right and wrong, therefore, the might ask for something which is not suitable or the mothers are not willing to do for example, buying an expensive toy etc. Therefore, mothers start lying to them in different way in order to convince the kids that it is not appropriate for them. In this way, women not only find lying easy but it lets them go from other questions which their kids might ask.
Also, mothers get into the habit of lying as they want to project a perfect life to their kids and show them only the good side of life along with a perfect personality. Lying often hides the true facts about life and the real ups and downs for children as they easily believe in what is being told to them and what they see is being projected.