I noticed it was often the case: I read (or listen to) an interview, or a short article by some author, and I tell myself "this is brilliant, I'd like to read a

I noticed it was often the case: I read (or listen to) an interview, or a short article by some author, and I tell myself "this is brilliant, I'd like to read a deeper development about this theory/point of view/..., oh, he's written a book, perfect!". Then I buy the book, and there are 30 pages about the specific point the author promoted in media (often with exact same sentences), and the other 200 pages are a disappointment. The data supporting the point is cherry-picked, or further development is fanciful, or there is a lot of page filling, or the other chapters seem (to me) mostly unrelated, or the author spends half of the time boasting and quoting himself (the books as full of notes and quotations from other authors as doctor theses are another evil).