Many people agree on the words proposed by GoF, but not on the details of the meaning, and this is a frequent source of misunderstandings and useless debates. Over the years I have gone from fan of the book to considering it a net negative force in software engineering, a failed attempt that many people still believe in. (The other failure of the book is in educating people to blindly believe that applying a given pattern is always a good solution because, hey, it's a pattern)

If you look at the details of the patterns as examples rather than definitions, and treat on the book as a general description of common situations, problems and approaches, then all is well.