A Green Hat is someone who is fully dedicated to Trading. They don't allow anything to distract them from their focus, and they're constantly thinking about trading.
They're passionate about the subject and enjoy watching movies related to trading, such as The Wolf of Wall Street, The Big Short, Margin Call, Wall Street I & II, Rogue Trader, Inside job & Too Big to Fail. They might even watch these movies more than once, although they may not readily admit it.