Do you always eat only the finest meals, freshly prepared, with only the highest-quality meats and produce?
Sometimes an In-n-Out burger can be "wonderful".
I, too, enjoyed Chaos. Regardless of its inaccuracies -- wherever they are -- it presents the topic very well, introducing it without being dry or unreadable. It held my attention throughout the book, and I still remember specific parts of it. I wouldn't mind reading it again, either.
Books, like business, can have different markets and do different things well. I think what Gleick lacks in writing a textbook, he makes up for in approachability.