Linguistics (and its sister study philology).

By that, I don't mean learning a bunch of languages, but studying about language in general; how it works, how it develops and changes, how it influences our minds, societies, culture, and everything else. It's not studying languages; it's studying language.

There's so much to learn and know about it. It's amazing and wonderful how much a crucial part of us and our lives language is, and how much does it shape our world. There isn't a scientific study I know of that wouldn't be useful in studying language, it's that much ingrained in us. Slang and dialects are especially interesting, as well as historical and comparative linguistics. I am also super interested in general linguistics, as well as history of linguistics (=/= historical linguistics)

The only people I met who were genuinely interested in linguisitcs were on the internet. Most people in real life confuse it with literature or polyglottism, or being a grammar Nazi.

Another one is animation, or should I say, animated films. I've never been interested in animating, but I always loved watching cartoons and animated films. History of animation is another extremely interesting topic to discuss, but most people I know don't watch cartoons, think it's something for kids or weaboos, or are just not that into it.