Well, it’s simple in order to have a conversation which is funny and long, we start with insults and by saying something sarcastic about that person.
We can start with compliments too, but it just not fits and it’s not funny & also because they are too formal and short timed.
And we are all designed to respond quickly to something we don’t like and also by saying so, we can attract someone’s attention very fast.
In case of boys, they are cannot talk to the girl they like in a nice way. So, they start with doing jokes and annoying her or commenting on her. Boys cannot talk about feelings, they may show but they won’t say it out loud.
In case of girls, if they like a boy, they just want to have conversation with him irrespective of topic. They just want to talk to him.
P.S.The most amazing thing is they will fight in front of their friends but when alone they will be nice to each other and will talk about feelings, goals, everything. It’s like they are best friends when alone but in front of their friends they are like enemies or hate each other and will kill each other if given the opportunity. They do so as they are clueless and don’t know how to process their feeling in front of their friends. It’s easy to show your anger or dissatisfaction than love and likeness. So, they end up fighting.