Of course it's my fault for missing the tiny difference. On the other hand, they could also design better. Put post-it style (meaning easily removable) stickers on the different parts so the instructions can call out the step 5 needs the parts with the stickers, not the parts without. Etc...
I got cabinet from Wayfair, I don't remember the brand but the instructions were surprisingly better. As just one example they had put every set of parts it it's own numbered bag. The bags were all one long strip (kind of like the way zots candy's come) where each portion of the long crimped bag had different parts and a number printed on the bag. The instructions then referred to the bag. Vs Ikea where all the parts are in a single bag and it can be difficult to notice some of the bolts are 60mm and others are 64mm
I've never failed to correctly build Ikea furniture and I've probably built ~60+ pieces but there is arguably room for improvement.
- branching paths aren't well marked
- I often find typos (e.g. go to page 16 when it's really page 17)
- parts page sometimes doesn't match the supplied parts in terms of size and shape
- it's not always clear when parts are optional
- some things come as separate pieces and it's not clear how they go together as the instructions are for each piece and not the entire assembly