I didn't read the book, but being boring is Tarkovsky's touch, so it sounds pretty safe to say it comes from him.
Also people, please don't downvote parent. It's very fair to say this movie is boring and confusing, and I think it was the very point. Tarkovsky has this style of filming around supernatural / sf things but never actually showing them. Instead, he prefers to explore the anxiety they cause on humans, anxiety which he often represents through long waiting with deceptive conclusions, so I would say that feeling annoyed is quite what is expected from people watching them. It's art, not entertainment.
Also people, please don't downvote parent. It's very fair to say this movie is boring and confusing, and I think it was the very point. Tarkovsky has this style of filming around supernatural / sf things but never actually showing them. Instead, he prefers to explore the anxiety they cause on humans, anxiety which he often represents through long waiting with deceptive conclusions, so I would say that feeling annoyed is quite what is expected from people watching them. It's art, not entertainment.