1 Mind loves novelty
The human mind loves novelty and is never fully satisfied - even if it encounters perfection. Sooner or later it will start looking for a better replacement. Because of this, things that are different than the norm subconsciously get more attention than those that are common.
2 Predictability devalues the message and provides early answers
If people are warned beforehand that there's an unusual plot twist in a movie or book, the chances of guessing it are greatly increased. One example is knowing there's a twist in the movie 'Sixth Sense' made people realize the main character's fate within the first 5 minutes.
3 Variations in reading patterns to stimulate the reader
To increase the reader's interest in text, authors use various techniques to keep readers motivated and engaged. Some of these are breaking the text into smaller paragraphs, various font sizes, various font colors, making the consciousness take a break by showing an image, and so on.
4 Really short time to get attention
Currently, humanity's attention span is only 8 seconds. Within this short time period is a chance to get the client's attention before he shifts it to somewhere else. Predictability will make the client leave disinterested even before the 8 seconds are up. Monotony is avoided almost immediately.
5 TV is adapting through 'snapback'
A research conducted by Turner Broadcasting showed how 54% of TV viewers surf the internet while watching TV but only 10% of them are looking for content related to TV content being showed. In order to get their viewers back, they're using the 'snapback' method-sudden loud sound effects and music.
6 Keeping the message fresh
Whether it's a TV ad, web ad, newspaper ad, presentation, website, Facebook status - it has to remain fresh, novel, and creative in order to retain the audience's interest. Making the extra effort to think of and produce something new will be noticed by the audience and possibly bring new clients.
7 Google Doodle example
Google sometimes changes its logo and adds interesting features to it, such as funny games and animations. This is done to celebrate a special event but also to break off from the monotony and come off as a more exciting and interesting company. If the competition doesn't catch up, Google wins.
8 Game of Thrones example
The popular TV series Game of Thrones is anything but predictable. Minor and major characters go through unpredictable, often shocking events and are even killed without any prior warning. The audience can hardly predict what's going to happen next and this keeps them glued to their TV screens.