In design, great effort is put into making things predictable, intuitive even. Buttons in the right place, switches that turn things on and off consistently, nothing needlessly complicated. The official term is Affordance. And great pains are taken to Keep It Simple Stupid when creating something new.
Obvious advantages to this are: less frustration for the user and faster more streamlined processes. People can automate processes more easily, saving valuable brain power. If it’s easy, you’re more likely to use and do it again.
However, when it comes to advertising, you want the opposite. You need to attract attention. You want to disrupt the pattern that people have ingrained within their daily lives. If they ignore what you’re doing, how will they ever notice your new amazing thing you’ve created? They may even prefer it.
In this respect, advertising has to be consistently unpredictable. New ideas that disrupt, interrupt and break routine. Anything to catch your attention. And attention is very precious these days. There’s so much information out there - what should we pay attention to?
Things that are ok to be unpredictable:
3) thrill rides
4) plots for movies and books
5) ideas for inventions
Things not ok to be unpredictable:
1) electricity supply
2) locking gates at the dangerous animals enclosure
3) brakes on a car
7) list numbering