In life,I have learnt that people are different and your method of coping with them should differ.While some people are easy to cope with, some people are just soo impossible to cope with.They know how to press your button and rub you up the wrong way.
Instead of throwing tantrums and lashing out at them, their are better ways to cope with them before you lose your sanity.
Personality disorders are always notoriously difficult to treat .Well, I may probably say you should initiate no contact and run but the question is,what if the narcissist is your boss and you need that job or your spouse that you have kids for,then you need to look for other ways of dealing with them.
The fact is narcissists were not appreciated when growing up ,they were not given secure love .They are only appreciated for what they have achieved.Due to this fact,they grow up not trusting anybody and being ashamed of their human frailties.
For narcissists,empathy is more like an under developed muscle. You need to help them develop this empathy muscle.Calling them jerks or lashing out at them only makes things worse.
When they are constantly reminded of the importance of their relationship and how the relationship can make them achieve their goal ,they will improve.
Taking a swipe at them everytime is not just a good way to go.You can check online for other ways of coping with narcissists. There are tons of tips on the internet on how to live and cope with a narcissist.