The best party banter I've ever experienced is from Warhammer: The End Times - Vermintide
Banter clip I think a lot more games could do something along the lines of this, especially when you want a person to reveal their character's personality/backstory mid-way through an adventure. It's fun to hear and often enlightening, adding to a character's persona and making them that much more interesting, likable or unlikable when accompanied with multiple people.
