If you want to put it that way, you can think of information in the user's brain as being stored in peripheral memory at the end of a horribly slow, high-latency, unreliable bus. :)
Especially when you need the user to take an action: the API isn't well-formed (for example a mix of visual cues, text, and UX behavior) but at the end of the day if you give the user something to do (example: you want them to acknowledge and dismiss a notification or make a choice) there are multiple ways of doing it, some much faster and others much slower.
This is especially interesting when you need the user to deal with your bugs (e.g. errors of various kinds). It's not really part of what they're trying to do - you're the one that needs them to react somehow.
