#1. He's can't help bringing himself up in conversation.
"Really? You ate Kung Pao Chicken last night? You know, I make a pretty killer Kung Pao Chicken myself. And Garlic Fried Rice. And Wantons. I've been told my Chinese cooking is amazeballs."
#2. He needs you to tell him how he great he is, on the regular
If he's wearing a new shirt, you need to notice. And think that shirt looks THE best. And tell him, preferably three to four times that evening.
#3. He won't apologise after a fight
It doesn't matter if he bailed on dinner with your folks last minute—he'll stay adamant about the fact that he had to work late qualifies him to not fess up and say he's sorry for ditching.
#4. He'll find a way to make any discussion about him.
"Oh, honey, your parents are splitting up? That's awful! I remember, when my parents used to even fight,it used to drive me crazy. But I grew up pretty okay despite a deeply disturbed childhood, don't you think?
#5. He doesn't do well with orders
Not once, in any situation, can you TELL him what to do. You can ask, request, even subtly manipulate—but he prizes his own opinion and authority too highly to take orders from anybody.
#6. He's really goddamn charming
Narcissism = Self-Love. Self-Love = Confidence. Confidence = Oozing Charm like a melted-cheese free-for-all.
#7. Everything is a contest
If you've done it, they've done it better. If you're good at something, they're sure they could do be just as good if they tried it. If you have information on a subject, they're freaking Google. Yes, it will get incredibly exhausting.
#8. He really cares about what people think of him
Their 'image' is everything to them. If there's ever a chance your opinion of him is lowered by something he did, he'll go to the ends of the earth to fix it. Not because he's hurt you, oh no no—simply because his pristine reputation must remain intact. Which brings us to…
#9. Your feelings matter less than his
In a fight, he'll focus more on how he's been wronged than what he can do to smooth things over. "My mother not liking you means she disapproves of MY taste!"
#10. They don't understand the word 'No'
If you have plans on a night they want to spend with you, you'll eventually end up canceling. If you really don't like horror films, they'll convince you'll like this one. Just make sure he doesn't push you into changing your mind about stuff that's bigger than films and nights-out with the girls.