Design patterns aren’t solutions to common design problems. They’re after the fact descriptions of solutions for design problems. That’s the issue. That’s the beef. Everyone thought of that book as a cook book instead of a naturalists’ musings on an ecosystem, which is what they are.
Those of us who designed before people discovered that stupid book were constantly asked what the differences were between this pattern and that. And the book just isn’t thick enough and Eric Gamma was just trying to complete a thesis not write a book, so despite having at least 8 years in industry before completing his masters he cocked it up. And ruined Java in the process.
We had a contemporary of Vlissades teach a class at my last company and he crystallized all of my suspicions about the GoF book and added a whole lot more.
My advice for at least fifteen years is, if you think you want to read GoF, read Refactoring instead. If you’ve read Refactoring and still want to read GoF, read Refactoring a second time because it didn’t all sink in.
Refactoring is ten times the value of GoF for teaching you how to do this trade and how to break up architectural brambles.