This one pops up a lot - I love the design and poster aspect. I am always amazed how many of these 'Laws' trace back to Nielsen Norman Group data and research over the years. Many UX trends are even named after them! Jakobs law... Norman Door. UX professionals are being greatly influenced by this focused observer set. Maybe just my opinion, but modern UX and HCI theory is being held back day by day due to a set of gentle rules. Specifically, 'Rules' from exposed patterns across user experiences in Broadcast and other non-interactive media.