If you're willing to read eighteenth century german, I found the original Knigge book interesting. The modern world has enshittified his name into MOR manners g

If you're willing to read eighteenth century german, I found the original Knigge book interesting. The modern world has enshittified his name into MOR manners guides, but the book he wrote (1788) was all about "here are a bunch of different types of people you might meet and these are the conversational topics I've found best to pursue (or avoid) with each type" — a very different vibe!