Have you yelled 'Boo!' at someone and then felt foolish when they weren't frightened? Scaring people is a complicated business.
Rico Patel became a scare master when he started working at a tourist attraction in London, scaring visitors every day.
He was so successful at his first job that he now travels around the world, recruiting actors for different attractions, teaching them how to scare people.
'Scaring people is not about haunted houses, or pretending that we are Casper the Ghost. We portray ourselves as serial killers; and it's all about having the control and focus to get into someone's personal space,' Patel says.
In order to better understand the nature of fear, Patel reads up on psychology. He looks into the psychology of fear, and also into how the minds of serial killers work.
'Serial killers ... are very focused. Actors [in scare attractions] have to [put themselves into the mindset of] serial killers so that they can focus for the show,' he says.
Patel says scaring from afar is much less effective than invading someone's personal space. You've also got to avoid laughing or joking, or you'll fail to create genuine fear.