But he wasn't Japanese.

Could you form any impression of his ethnicity, nationality or where and at what age he learned English?  I have had well educated English speaking Chinese ex-patriots in Los Angeles inform me that they didn't particularly like Japanese people.  The occupation of Manchuria, the Rape of Nanking, etc. happened to many living peoples parents or grandparents.  Same thing for Vietnam and the Philippines.  And I won't even start on Korea.

Did he have any reason to think that no one in line at McDonalds would understand the conversation he was attempting to have with you?  Was it your impression that any of them did?  Could he be someone who was working in Japan and who has just lost their job?  His verbal behavior does not seem likely to serve him well in Japan, especially now, with so much suppressed anxiety among the native Japanese.

A fascinating diary.  Did you discuss this with anyone at your department barbecue?  If so, how did they react.    

"It is not necessary to have hope in order to persevere."