Trash talking happens more as a release i feel then doing any kind of good, having a 3rd or more watching dong the talking as the fighters glare never hurts one’s ego, but as for me most of the “trash talking” is a taunt or threat to do a certain thing to the opponent or something like “thought you were gonna kick my ass” beyond that i tend to be busy thinking of a move or counter move ahead over something to say, take into account are you asking as a arranged rule meetings go or on the street ?