How often are you part of a conversation that you really aren’t a part of?

Ugh, it used to happen heaps!
My ex was one of those people who could have an entire conversation in their head, and believed it had happened.

So itd go like this :
Him:*sitting at computer* "What car is your favorite?"*shows me photos*
Me: "that one looks nice, why ?"
Him: "oh, just wondered really".

Two weeks later:
*new car in driveway*
Me: "who's car is that?"
Him: *looking pleased* "ours, i just got it, its the one you liked".

Me:😱🤬🤯

Argument ensures.......

It was maddening.