Most RPGing involves conflict and opposition as a crucial component of the fiction: the player characters are trying to overcome some sort of opposition or antagonism.
Not all RPGing is all antagonism all the time - eg if a group spends an hour settling equipment lists for the PCs that is more likely to involve referring to lists and transcribing information than engaging with antagonism in a shared fiction; or if a group spends an hour in which the players all, in character, speak to one another about their recent deeds and make plans for future deeds, there may not be much confronting of opposition in that episdoe of play.
Still, I think it's fair to say that opposition/antagonism is pretty important to most RPGing, although of course it comes in different forms: opposed people/creatures who want to thwart the PCs' goals; people/creatures who have goals that the PCs are opposed to; places that the PCs wish to enter or pass through but that are not easily navigated (due to geography, or architecture, or fixtures like traps, etc); and no doubt many other forms too.
Because the opposition/antagonism is a component of a fiction, someone has to come up with it. And because it is related to the PCs in a hostile fashion - it is at odds with what they want - someone has to establish that relationship, of PC wants as a component of the fiction to this other, oppositional, component of the fiction.
In your RPGing, who does all this? And how is it done?