agree with what pchristensen said. a lot of people read HTWFAIP and the next week they're smarmily complimenting everyone. when this doesn't work they assume the book is bull shit and go about their lives. this isn't how it works. the compliments have to be genuine. as mentioned in the anecdote, the compliment is just a way to segue from business into genuine engagement with the other person. this would never work if the compliment wasn't about something of substance.

anyhoo. the main thing I took from the book in combination with everything I've learned about behaviorism and cognitive bias leads me to believe that the underlying trick is to bolster people's internal narratives. everyone constructs a narrative of their life in which they're the hero, validating this narrative will win you loyalty like you wouldn't believe as deep down, it's a major part of what everyone wants.