Although the course does say that diving is different in different places, I will also say that for a new diver, the differences can be really surprising. I have my own memories to show me that.
After certification, I did all my dives for the first couple of years of my diving life in Cozumel, where the DM sets your gear up for you and leads the dive. Then I did a dive in South Florida. I got my gear on the boat, and as the boat headed out, I sat quietly waiting for the DM to come over and set things up for me. It was a while before it dawned on me that I was on my own. (Let me see now, how do I do this again?) When it got time for me to get in the water, I was again surprised to find out that there was not going to be a DM in the water.
So I was unprepared for the differences. It was not because I was afraid to ask--it was because I did not know there were differences to ask about.
I assure you that there are people who get their OW and then dive for year after year after year in places where DMs set up their gear and lead their dives. It is not surprising that they think that is how it is done everywhere. It is not surprising that when they come to a place where it is different, they have forgotten their initial training on gear setup and dive planning.
As an instructor, I have on several occasions had students tell me that their experienced diver friends assured them that once they had passed the final exam, they could forget all of that dive planning stuff, because in the real world the DM does all of that for you.
