Something that's been bugging me all weekend and still thinking about it today - Why would this guy do this?

Ok here's the deal, I work part time at a call center and while working this past Saturday I took a call from this one man. I immediately greeted him with the normal greeting we have in our script. He then immediately asked me, 'Are you American?' Which I am, so I replied, 'Yes'. To which he responded, 'Are ya?' Then I said, 'Yessss, Do I not sound American?' Then he replied, 'No, no you do' and then he hung up on me!! I've been thinking about this call since I took it this past Saturday. I usually just brush off prank or mean calls, but for some reason this call's just stuck in my mind. I wished I could have replied with something such as, 'Yes sir I am American. Is there some sort of problem or may I go ahead and continue with your order today?' But I didn't get enuf time to think about it. Just wonderin, why would someone ask me this and then hang up on me? BTW I don't have any accent except for maybe a lil bit of a Texan one because that's where I'm origianlly from.