As long as it's natural and fits the atmosphere of the game.
Like, if no one swore in GTA or Catherine, that would be really awkward.
But I think unless it is necessary to use obscenities in dialogue to portray a character or society or whatever, it shouldn't really be used. --- Just wake me up when Tokimeki Memorial 4 is announced. g Rod "hing RodCopper Fishin For fishing.