Learning which steps in a process are unnecessary is one of the hardest things to learn. Steps that are unnecessary yet harmless can easily be worked into a routine, and because they cause no problems apart from the waste of time, don’t readily appear as problems.
An example. A few years ago a (not very technical) colleague was demonstrating something to me on their computer at work. At one point, I asked them to google something, and they opened the web browser, typed the URL of the University home page into the browser, went to that page, then typed the Google URL into the browser, went the Google home page, and then typed their query. This was not at trivial time cost; they were a hunt-and-peck typist who took a good 20-30 seconds to type each URL.
Why did they do the unnecessary step of going to the University home page first? Principally because when they had first seen someone use Google, that person had been at the University home page, and then gone to the Google page; they interpreted being at the University home page as some kind of precondition for going to Google. Moreover, it was harmless—it didn’t stop them from doing what they set out to do, and so it wasn’t flagged up to them that it was a problem. Indeed, they had built a vague mental model of what they were doing—by going to the University home page, they were somehow “logging on”, or “telling Google that this was a search from our University”. It was only on demonstrating it to me that it became clear that it was redundant, because I asked why they were doing it.
Another example. When I first learned C++, I put semicolons after the brackets at the end of each block, after the curly bracket. Again, this is harmless: all it does is to insert some null statements into the code, which I assume the compiler strips out at optimisation. Again, I had a decent mental model for this: a vague notion of “you put semicolons at the end of meaningful units to mark the end”. It was only when I started to look at other people’s code in detail that I realised that this was unnecessary.
Learning these is hard, and usually requires us to either look carefully at external examples and compare them to our behaviour, or for a more experienced person to point them out to us. In many cases it isn’t all that important; all you lose is a bit of time. But, sometimes it can mark you out as a rube, with worse consequences than wasting a few seconds of time; an error like this can cause people to think “if they don’t know something as simple as that, then what else don’t they know?”.