Swipe from bottom to switch programs? Swipe from top left and top right to get different (IMPORTANT!) panels? Why are three lines a "Menu"? But sometimes it's dots, or a gear icon, and they're never in the same place. On iPhone, there's no real unified "Back" button - chase it down from application to application with different context and result every time. On Android, unified buttons (including reliable and predictable "back") exist but their location and icons are not intuitive either.
I also encountered opposite problem than described - when I tell people to hold-press, they exert force. It's a natural, intuitive thing for most of them - they're trying to press hard. But the mere notion you need to hold-press anything? Completely unintuitive. Like everything else on a modern phone :-/