Hello Tildes! I often find myself intimidated by authors of great sagas, trilogies upon trilogies, and dozens of standalone novels. How do I know which book (or series) to read first?

I've been recommended Terry Pratchett and Brandon Sanderson recently. I've read zero novels by either author. I've also been warned that there is a definitive best place in the canon to start, "and it's this one!" But then someone else interjects and says, "no, it's this one!" followed by passionate reasoning. Okay. If it is really worth starting somewhere in particular, where should I begin?

I'm unlikely to read an author's entire corpus. I just have too many books to read and not enough time. But I'm not opposed to reading longer series if they're really fun. I'd appreciate any input about these authors in particular and this problem in general. Thanks!

Some (hopefully obvious) caveats before we begin.

1. By definition, everyone sharing examples here has not deeply engaged with the source material, so they're likely to have misconceptions from cultural osmosis.
2. If you have read the source, feel free to share whether the common knowledge is accurate, a common misconception, or the first time you've seen it interpreted that way.
3. If it was a video game, classical music, or other non-book that influenced you, those are also welcome.

Some answers from asking a similar question elsewhere

• Marx
• The Bible
• F.A. Hayek
• Aristotle
• Milton Friedman
• Socrates
• Plato

I'll post my answer as a comment to give it equal weight to the others.