In n' Out Burgers correlates with California, which correlates with NOT being from the Northeast, which correlates with being, relatively, calm and relaxed.
Why are Californians chiller than others? I wonder if it's actually true
Californian here. Yes, we are. It's the nice weather.
It's because you're looking at it from the wrong direction. The indicators are selected because people who are shy have a higher than average likelihood of liking "programmers". If you average out a bunch of likes and you know the general personality types of people who like those groups you end up with a pretty good general picture of someones personality.
I really want to see this run on one of those profiles that facebook marketing clickbots use.