These deserve a much fuller treatment than given here.
I tried to learn Blender a year or so ago - a product with a notoriously inscrutable user interface. All the tutorials are in video form and EVERY SINGLE ONE includes at least five minutes of some microcephalic idiot saying "um" a lot, explaining what product the tutorial is about (thanks, I know, that's why I'm watching the tutorial), saying "um" some more, explaining what he's going to explain in the tutorial (thanks, I know, that's why I'm watching the tutorial), saying "ah" quite a bit, presumably to alleviate the boredom (his, not mine) and explaining why you'd want to do what he's going to explain in the tutorial (thanks, I know, that WHY i'M WATCHING THE FS!CKING TUTORIAL). It's as though they expect people to just sit there watching a random stream of tutorial videos and so need to say up front what the tutorial's about.
Another pet peeve is websites that do have a 'Documentation' tab but, when you get there, have an explanation of how great the product is but no actual instructions on how to use it (yes, www.beremiz.org, I'm looking at you). Or even worse, a documentation link that leads to an empty wiki - See? It's YOUR fault there's no documentation, you haven't created it yet!