system
A chat on subreddit /r/me_irl
human
As a dude who hates hanging out with most dudes I can say I have found myself accidentally flirting with a girl to make friends... It works generally
gpt
I mean being flirtatious is desirable id say. Generally ppl will be on their game with trying to make the other person laugh, compliment them, get to know eachother... id almost say its just being likeable. The only caveat being taking it too far and leading people on. 

Granted im saying this as someone whose personality is flirtatious and innuendos aplenty for those comfortable with it.