Certain lines should not be crossed, and it’s important to repair them.
For that, keep in mind you have to validate the other person’s feelings and acknowledge the fact they experience things differently than you do.

It’s not necessarily a bad thing to fight

Love & Relationships

<ul>
<li>The first dynamic of an argument: you gather the information that reinforces your beliefs and neglect information that challenges them.</li>
<li>The second dynamic: the negative attribution theory.&nbsp;If I’m treating you poorly, it’s because I had a bad day.</li>
<li>The third dynamic: the negative escalation cycle. This is when we instigate from a person the very behavior we don’t want.</li>
</ul>

The form fights take

<ul>
<li>"Holding: the absolute truth: We think that when we say something during a conflict, it is an absolute truth rather than a reflection of an experience.&nbsp;If I feel it, then it must be a fact.</li>
<li> Using the words "always" and "never:" I always do all the work/You never help with the work. Nobody likes to be defined by someone else.</li>
<li> Chronic criticism: It happens when you criticize so much that you leave the other person feeling like he can never do anything right.</li>
</ul>

Mistakes during arguments

When you’re in an argument, before you disagree, try telling the person you’re speaking with what you heard them say. 
When you’re in a disagreement, you are able to repeat what the other person said for only 10 seconds. After that, you go on with your answer or tune out. But it’s important to repeat what was said so they feel acknowledged.

Switching from reacting to reflecting

We get into arguments because we want to feel that the other person respects what we’re experiencing. Saying "I can see where you’re coming from" is a great form of validation.
When your experience is acknowledged, you feel sane. So even if you don't agree with the other point of view, it helps to acknowledge that there’s another person who experiences the same event very differently from you.