Behavioral economics was my favorite and I’d say it’s tied closely to game at its core, they’re both trying to predict human choices game theory just tries to quantify it with math. None of it is “pure math” it’s all theory with math attempting to support it. It’s only in like the last 100 years math even came into economic theory. I always enjoyed reading theory from the less recent economists (before they were even called economists) because it’s more pure theory/philosophy.