Did Rob Janoff really considered the Fibonacci series while designing it, or is it a coincidence? Well, somebody needs to ask Mr. Janoff. Interestingly, in a different context, in an interview, Rob Janoff said, “… and years later you find out supposedly why you did certain things. And, they are all BS. It’s a wonderful urban legend.”

Full stop question and answer: http://creativebits.org/interview/interview_rob_janoff_designer_apple_logo

RJ: They are really interesting, but I'm afraid it didn't have a thing to do with it. From a designer's point of view and you probably experienced this, one of the big phenomena is having the experience of designing a logo for whatever reasons you design it, and years later you find out supposedly why you did certain things. And, they are all BS. It's a wonderful urban legend. Somebody starts it and then people go "oh yeah, that must be it".

Forward backwards or backwards forward?

The golden ratio is a mathematical explanation of what humans find beautiful.

He didn't know the math. He just made what he believed to be beautiful.