"Build an emotional roller coaster. Viewers are most likely to continue watching a video ad if they experience emotional ups and downs. This fits with psychological-research findings about human adaptability. When we come into a warm home on a cold winter day, or when we receive a pay raise, we experience pleasure, but the feeling is transitory; the novelty soon wears off. So advertisers need to briefly terminate viewers’ feelings of joy or surprise and then quickly restore them, creating an emotional roller coaster—much the way a movie generates suspense by alternating tension and relief."
The New Science of Viral Ads - Harvard Business Review
