I notice I'm rationalizing when after I lose my first defensive argument, I have another lined up and ready to go. If that continues in succession (2 or 3), then I have to stop and rethink my position.

I have a thought in my head that tells me "I'm being irrational", and I try to shut it off, or not care about it. Usually this leads to an increased level of frustration and anger.

When in my mind I already realized I'll have to change my opinion, but I don't want to admit that right now, during the argument.