Mystery explains Negs
Notice all they are are witty playful busting. The reason he does this is to show he's game, that the two of them are on the same level. Hot women usually have guys being very weak and supplicating. He does the opposite and challenges them, sometimes brashly.
Here's a bit Neg Theory right out of the Mystery Method book:
NEG: Verb, noun: a statment or action made to briefly and without insult disqualify oneself from being perceived as a potential suitor.
Usage: to neg someone, to be negged, to throw negs, to master negging.
A neg is not an insult but a negative social value judgement that is telegraphed. It's the same as if you pulled out a tissue and blew your nose. There's nothing insulting about blowing your nose. You haven't explicitly rejected her. But at the same time , she will feel that you aren't even trying to impress her. This makes her curious as to why and makes you a challenge. (emphasis mine)