James Jones and the Trusty Turtleneck

I've always wondered why James Jones wears a turtleneck. In more than a few pictures of Jones, it looks like he's either wearing a turtleneck or something like a turtleneck. But occasionally, the neck part of the turtleneck won't be the same color as the sleeves, and that's always puzzled me. Now we have an answer.

http://instagram.com/p/c7TlFjDyNW/

Turns out, James Jones is not wearing a turtleneck after all. Well, he is, but it's a weird cutoff thing. But now I have more questions.

Why is the shirt not a whole shirt? When did he start wearing this kind of shirt? Why did he do it? Is it comfortable?

James, I have so many questions. Please tell me about your turtleneck.