Do you all have memories worse than mine? Don't any of you remember being a pre-solo student? Or were you all natural pilots who picked it up like that? I remember (and I'm talking f/w here, not rotary). Snigs is right. You may have the circuit all clear in your head, you can talk it through, visualise it, fly it in the open FIR, do the checks. When you get into the real circuit, with other traffic, and specific places to turn, and someone answering your radio calls etc etc, that represents overload...at least it did for me, and I'm sure I'm not unique.
So sticking to the standard pattern is great, but I still remember my panic from an over-zealous instructor demanding that I turn base NOW, when I was still getting sorted out, and believe me, it didn't do me or my flying any good in the longer term.