The results don't confuse me as much as the study itself. If they were looking for the city that's home to the most annoying, boring, self-indulgent Twitter addicts, I suppose "good morning" would be a good phrase to track. Although I'm not actually on Twitter, so maybe I'm wrong. Maybe their followers enjoy reading inane tweets and appreciate being reminded of when people are waking up in various time zones.
Come to think of it, I don't much like people saying "good morning" to me offline, either. If it's a colleague in the office kitchen, I fear being roped into small talk about her weekend putting together a jigsaw puzzle. And if it's a strange man on the street who also tells me to smile, I have to resist the urge to respond with "f*** you" -- because that is decidedly rude, especially in (even in?) the Midwest.
Photo source: http://www.dailymail.co.uk/news/article-2191250/Twitter-heat-map-tracks-polite-rudest-cities.html