In many perspectives and opinions, lying has many causes, namely;
1 - To hide the truth
2 - To provide half-truths (partially accurate information)
3 - To uncover the truth (leading the other party to leak out information unintentionally)
4 - To hide another lie
5 - To build upon the original or subsequent lies
Fundamentally, many debated upon lying, as to the morals and values for lying. Is lying never right? Is lying always wrong?
In most aspects, under general circumstances, lying IS wrong, unjustified and at times, inflict dire consequences unto oneself or others. Some of these lies have singular effects while others have multitude effects capable of crippling a society, governance, nation or even across the globe. Understanding lies may help to uncover the general reasons being liars but in attempt, may also influence one to become a fluent liar.
So putting aside all the definitions, uses, causes, effects and types of lie and liar,it is come to conclude on one question, why do lies exist?
1 - To protect on personal or general desires both positively and negatively benefiting
2 - To help in both good and bad causes
3 - To control those in ignorance both justified and unjustified for power, etc...
4 - To mislead or guide those in ignorance or in knowledge both beneficiary and detrimental
The depth of usage for lies as well as the range of purpose for lies are countless both for good and bad. In order to know on simplicity levels whether lying is truly good or bad, the true intention on use is required to be known as lies themselves could be truths used to hide truths themselves. Regardless the skills, methods or functions or a lie, so long as it is used, even a child may unwittingly succeed in doing good or evil on a scale notably to the entire universe.
Conclusively, to lie for evil is wrong but to lie for truth and truth in itself MAY not be defined as right nor wrong.