When developing conflict in your story in dialogue, your can have one character remember about a past event when the other character was mean or unfair to them. For example, " Bob said, 'Jean, I have put up with this stuff for too long now!' 'Bob, what do you mean YOU'VE put up with stuff! Do you remember in Fall of 1988 when YOU...' "
In the past,
Professional Speech Coach
Free speaking tips at: http://speakingquicktips.blogspot.com