I acquired and read an adventure yesterday that I don't even know if I can call an adventure, it was so short! Only 3 pages, absurd... How can anyone write something decent in so few pages??

To use the correct term and avoid some annoying person saying otherwise, the term is "scenario," because it's a "scenario" for Call of Cthulhu. And so, the writing isn't bad, but it's hard to get a taste of it in the game. The best adventures are 30~50 pages or more, you know, where you and your group can enjoy every detail at your leisure.

I won't mention the adventure here in the post because I don't know if it's allowed... these days people delete things for anything.