Narcissists Are Liars
If you have a narcissistic loved one, chances are you are familiar with narcissistic lies. They lie about big things, they lie about small things, they lie for no reason at all. Like the old saying goes, "They'd lie if the truth sounded better." This is very frustrating because it's hard to have any kind of relationship with someone if you can't believe anything they say. You can't trust them and you can't depend on them. Honesty is a cornerstone of intimacy, so it's no surprise that - as narcissists are pathologically afraid of intimacy - they would have issues in this area.
Narcissistic people lie for a few reasons. Some are the same as the reasons most people lie, and some are not. They may be trying to boost their own false image, they may be trying to get out of trouble or avoid responsibility, they may be being contrary or it may be that they simply have a different truth today. Sometimes it seems that truth is a convenience to pathologically narcissistic people, and that can often be the case. But it's also true that to narcissists, feelings are facts. Therefore, their truth is defined by their mood. That's one reason they seem to contradict themselves so much. One day, their job is the best thing that ever happened to them and they could not love it more. The next day, something happens that discourages or upsets them and it's the worst job ever. They may deny anything good about it, they may deny ever saying that they loved it or ever feeling that way. This is because, the way their brains work, they can't "remember" good things when they are upset.
Narcissists have a very hard time taking a complete view of something. They are often unable to view both positive and negative attributes of the same thing at the same time. It's one or the other. This is sometimes called black and white thinking. It isn't that they are telling lies, exactly. It's that they just are not able to see things the way adult people do.
Now, there are some times when they are definitely lying on purpose. They may lie for sympathy, or to make themselves appear to be something they're not. We've all known people like that. They brag about things that aren't true, or make tragedies up that didn't happen. Some narcissists lie about abuse for these reasons, either pretending that what happened to them was much worse than it actually was, or conversely, pretending they were not mistreated at all because of their misguided idea that being abused means something is wrong with the victim. They may lie about how much money they have, what their job is, how many people they've slept with, who their friends are... all in an attempt to make themselves seem like something they are not. It's kind of sad, when you think about it. Being so uncomfortable with - and rejecting of - yourself that you have to pretend you are somebody else just to be able to live your life or just to feel that you have value.
Narcissists also lie to get out of trouble or avoid responsibility. "I didn't know you didn't want me to do that," or "I didn't do that, it must be a mistake" or "You said, you told me, you implied..." These are statements designed to create a situation where they can avoid responsibility. Gaslighting can also be an example of that. Think of a child sneaking a chocolate bar. It's all over their face and hands. You say, "Why are you eating that chocolate without asking?" and they say, "What chocolate?" It's the same basic premise.
Another reason pathologically narcissistic people might lie or change their story is because they are very contrary. It's like a toddler saying "No!" just to say no. It's not uncommon to be having an argument with a narcissistic person even though you are agreeing with them! Even when you are agreeing, they will continue to try to argue or may even change their argument to be opposite of yours so that there can be a difference of opinion. Narcissists are often struggling for identity and one of the ways an immature intellect will try to do achieve identity is through defiance and opposition. Children create identities by rebelling against their parents. It's similar to that. And sometimes it's about just wanting to fight. This is because they are often hostile and oppositional. Sometimes the argument is the goal.
Then there may be times that the narcissist in your life has lied for no good reason you can figure out. There seems to be no rhyme or reason for it. It's just something they do, and you may never figure out why. In the end, relationships are built on trust. If you cannot trust somebody, you can't build anything with them because there is no security in deceit. A - any relationship - relationship is like a house. It needs a strong foundation in order to last. If it doesn't have one, it is going to crumble.