Nah! that's why we have methods for adding comments to our code / scripts.
I script most things in VS so I don't often bother with the large majority of action parts. When I need a refresher of the data structure field & table names I just check on the wiki. & if I don't remember what something I wrote is for in one of my scripts then no worries as I've probably added comments above or to the side of most lines & functions to allow me to jog my memory.
My most used action part list consists of: if condition, if value, if character is on scene, change scene, show scene / menu, end if, pause, begin / end cutscene, show / hide cursor & display text.
In regards to Lua functions: I remember a lot of them because I use them quite often & it's only a step away to refresh my memory if I've forgotten something. One word - well technically it's a name: Google.
I doubt every programmer remembers every class name, every function for all the different scripting / programming languages they have learned. We don't come pre-built with photographic memory!