I recently had a pretty trippy experience at work: I had to do some simple frontend work (just add some tables with pricing information somewhere) and I thought "this is easy, just adding some markup and CSS, I know this".
But then it hit me: I had never done something like this *for work*, so I had never turned a professional design into markup. I was pretty lost as to how to tell sizes and such.
I felt like I was a n00b for the basic stuff, but proficient at the harder stuff 😬