if someone refers to themselves as a "history buff" or anything like that then they're usually some /r/historymemes tier shithead who only knows the most superficial elements of those three parts of history, for sure. i've found that people who actually know and understand a bit of history will show that they're knowledgeable about it when it comes up in conversation naturally but don't identify with the idea of being a "history nerd" because we all actually understand that we don't know shit about fuck and the complexity of the subject is more than any person could truly grasp.

like, the more i learn about things, the more i realise that history is a completely subjective discipline and there's infinitely more that we don't know than that we do. one example being with ancient history, you hear about egypt and mesopotamia so much more than you do about e.g. norte chico or the indus river valley civilisation simply because the former two have been studied so much more (in the western school anyway) and left behind far more that's of use to modern historians (written records, more substantial archeological remains, and so on).