I found out about the Expert Beginner book from Avdi Grimm’s newsletter. It is a small but discomforting book (a series of blog posts turned into a book) that I believe anyone in programming, systems administration or DevOps arena must devote some hours to read. Its basic premise is the following extension of the Dreyfus model:

While the book is a guide on how to spot and avoid Expert Beginners (people who believe they have mastered all there is to master in their field and anything beyond what they already know is useless), it also serves as a guide to spot when you start emitting Expert Beginner signals yourself.
Do yourself a favor and read the book. Especially if you consider yourself a guru, ninja or rockstar of something. It will only cost you two hours.