Go to one of those “local” cafes/bars etc – the sort of off the beaten track, avoid the tourist hordes places that get recommended in tourist guides which ironically has everyone who’s read the guide going to said “local” bar for that authentic experience.
And then you sit there watching all the actual locals who prop the place up daily being served and the conversation going on between them and the staff while being near invisible to them and waiting for service that may never happen. x2 if there’s a language barrier.