One of the greatest things about Classic D&D is, that to fully enjoy it, it almost requires you to understand the roots of things that we take for granted in fantasy gaming today. One big example is the race-as-class system, as I often hear people complain about the lack of freedom in class choice in Basic. "It's just dumb that I can't be a Dwarf Thief if I want". Setting aside that you can actually be a Dwarf Thief with some simple DM/Player creativity, I think modern fantasy literature and media has cheapened the meaning of a lot of the fundamentals of the game.
Before Tracy Hickman, RA Salvatore and other modern authors who wrote in much of the D&D universe, there were no Dwarf Thieves, or Dwarf Clerics for that matter. Dwarves were....Dwarves. Same thing with Elves and Halfl...er...Hobbits. Also, other than The Lord of the Rings, there were very few stories prior to the 1980s about people going on adventures to save the world, simply because they wanted to save it. Modern, what I call "pop-corn", fantasy has brought in a lot of tropes that never existed for a very long time in the genre. Now if that's your thing, great, but there's good reason behind many of the concepts in early D&D that many would shun today.
I personally feel this older fantasy is a far more pure recipe for the myths and legends that existed for thousands of years among hundreds of cultures. It's grittier, a little darker, and a little more slow-paced compared to the grander than life fantasy we get today. Appendix N is a great place to start to understand this better. But I'd take it even further than that, go back and study the most early fairy tales, legends and myths of western culture. There's a lot to learn about where all of our tropes took root and it may help you to get a better understanding of why things are the way they are in early D&D and, perhaps, why the modern game screwed things up a little too much along the way.