It never makes them play better. In fact, it does the opposite. It makes them play worse. They lose confidence and moral all in one shot. Once you begin to insult your teammates and start arguments you destroy your chances of coming back. It's like a more painful version of surrendering.
Did your jungler mistime smite allowing the other team to get dragon? Don't say "wtf dude how could you miss that", say "That's alright we'll get the next one."
Did someone push too far without wards and get caught out? Don't say "DUDE YOU MORON WHY DIDN'T YOU WARD?", say "Don't worry about it, just remember to ward next time"