When a person is bothered with something and after having a lot of practice with this, my take is that you're pretty much a jerk no matter what you say or do to him or her. The really hard part is staying persistent and really nice the whole time. It's really a matter of consistency that I've been looking for the whole time.
What I think makes a really nice person is never yelling at anyone no matter how angry or bothered you feel underneath. It's to also never make any threats to others about anything. I guess it's really hard to stay consistently nice while talking to someone. I've learned a few tactics that is really fun to try. Basically, one of them is to pretty much make counterpoints by redirecting the issue back at the other person and justifying it using facts. Even if it's making it up, it's a lot of fun to do this while you are talking and the other person is just fuming around.
Another thing is to go for ending the whole issue on the first round. Don't hold anything back and just drop the load without yelling at the person and be fully nice. My way is to pretty much never raise my voice and then use the counter method on the person. It pretty much passes the time and is actually a lot of fun to do. Another thing to do is to not even act like you are struggling. Just be honest about whatever you are feeling. The way I see it is if you came all from home and still thinking about this issue and going to engage then might as well just be honest about all the issues and even if there's a worry you might end up in a mental hospital or get some restraining orders; at least you can be very consistent in never yelling at anyone, being fully honest, and making counterpoints with the other person. Basically let the other person go all nuts with you while you stay very calm, collected, and nice the whole time while making strong points to keep you going. Remember to go for the knockout on the first round and don't hold anything back in your statements. Just be full on honest, but don't yell or make any angry struggles while the other person is acting that way with you. If you do this, then the other person is going to look bad with others and you are going to come up on top all the time. It's never too late to change your methods around and revert consistently back into this method now.