[golergka]

Same here. I often decide that the other person have stopped talking prematurely because they've made a long pause and I was eager to jump in.

However, if I notice that I have interrupted someone too late, I finish my point, and then say "but I've interrupted you, you were talking about X", and then make an effort to listen actively instead of coming up with thoughts of my own.

Sometimes, when we get carried away, I remind the other person of something he had been talking about so long ago that even he has forgotten about it. In my experience, being able not just go with the flow of the conversation, but keeping long conversation "stack traces" in mind so you can go back and actually "return" from a "subroutine" in your conversation is one of the most useful communication skills I have.