Yeah.
xD I didn't find The Silver Chair particularly scary, but I didn't honestly find it all that interesting, either. Not when compared to The Voyage of the dawn treader, The Magician's Nephew, or The Horse and His Boy. (Though I liked Puddleglum. :3)
Over all, Silver Chair was my second to least favorite, with The Last Battle being my least favorite. It was ... uncomfortable to read. Interesting, but uncomfortable. I respect C.S. Lewis's decisions for his world, but ... I don't have to like any of them and, in the case of that book, I didn't. I understand what he meant by it, still don't like it.
(Random? Well. Uh, that's technically true and technically not true. It was the sixth book written, absolutely, but it was the first book chronologically, you know. After all, it's a prequel to The Lion, The Witch, and The Wardrobe. The Pevensie kids weren't even a twinkle in daddy Pevensie's eye at the time, considering he presumably was either an infant or not even born...)