Fonzie's Jukebox

Looking into other people and seeing them exactly how they are is confounding because either I can't see anything recognizable or I see something that is alien and disturbing.
An interaction.  Names changed.
Me: Plover says the gathering is at his and Sparrow's place.
Finch: Their place?
Me: Yes.  How do you feel about that?
Finch: I don't have any definite feeling about that.
Me: I heard you say "Their place?" And I thought you meant "It's bad that the gathering is at their place."  And then I heard you say that you had no definite feeling about that and I thought you meant that you do have a definite feeling about that.
Finch: Well I just think it's funny that Plover would call Sparrow's place his place too when he just got back in town from months abroad and may not even be staying permanently.
Me: I'm confused because you didn't offer that opinion at first and it seemed to me that I had to coax it out of you.  What does that mean?
Finch: I just hadn't fully formed that thought yet and then it finally formed when you prompted me with questions.
Me: I am confused by that.
Finch: Unrelated thoughts about errands distracted me from my assessment of how I felt about Plover calling Sparrow's house his own but your questions restored my focus on the conversation.

I have experienced this before.  I call it Fonzie's Jukebox.  On the show Happy Days, the character Fonzie would often knock a jukebox with his fist to get it to work.  Sometimes it seems that people need a cognitive bump to get their thoughts going.  A prompt from another person to motivate them to complete a thought.  Not a sentence necessarily but a cognitive event.  Reputedly, this is common.  It isn't common to me; my cognitive processes move to completion on their own unless I am interrupted.  Prompting me is unnecessary and will derail my train of thought.  So it's very difficult to accept that other people might have thoughts which get stopped as they form, which trip on their other thoughts, or which form sluggishly without a nudge.  Hearing this is like hearing that it is common for people to need to see the color puce before they can turn left.  The idea is totally alien, totally strange.  And considering it leaves me feeling confused and dismayed.  Finch's plight may seem easy for others to understand.  Others who have experienced themselves what happened to Finch in this particular situation.  But not me.  I am confused enough and dismayed enough by what happens in other people's minds in general that I cannot conduct normal relationships.  How do I know when someone is being evasive, when someone needs a Fonzie knock to get their thoughts going again, or when they simply have nothing more to say?  I face daily minds that are entirely alien to me such that I can never find my footing to socialize and I am preoccupied with the problem.