I feel YOU are angry at me.
I feel like this is a . . . (these are thoughts vs. feelings)
I think YOU aren't listening.
YOU made me feel like I don't matter.
I feel nervous. What are you feeling?
I feel misunderstood.
I feel unheard.
I feel unimportant.
What's the difference; why does it matter?
There is nothing to argue with when we use an actual "I statement" because it just is how we feel in that moment. What, are you going to answer, "No, you don't feel unheard,"? I hope not. In order for there to be a sticking point, there has to be a hook to get caught on (think Velcro). Velcro needs two matched pieces in order to stick. When you simply state your feeling, you are a smooth surface.
No one wants to be told "You this" or "You that." So your partner is more likely to listen to you.
Of course your impulse to justify is often stronger than your desire to listen. Check in with yourself (not your partner) in this regard.
So, use I statements, and then reflect back what you heard (which is the only place for YOU statements).
You hear: I feel nervous. What are you feeling?
You Say: Oh, you're nervous. I'm feeling agitated.
You hear: I'm feeling agitated.
You Say: Oh, you're agitated. Will you tell me about that?
You hear: I feel misunderstood.
You Say: You feel misunderstood. What is important that you want me
Do you get the idea? It's slow, maybe you even think it's cheesy. However, it works. So experiment for yourself, and let me know how it goes.