You guys ever surprised by how ur coupled friends fights?

Just curious. I accidentally overheard my gay friends (who are a couple) fighting last night. We were hanging out and I stayed the night at their place. Woke up around 1am to use the restroom, and overheard their argument. Now, I have never even heard them bicker in front of me or any of our other friends. They are seemingly a perfect couple.

But this fight was straight up vicious and obscenity filled. Like I thought they were breaking up. Then in the morning in front of me they were completely normal. I was in shock.

Do all happy couples fight like this behind closed doors and behave normal in public?