.There seem to be a large number of people who startle easily and react violently beating on anyone or anything nearby. Then there are people like me who exploit this at every chance we get. Some you have to catch by surprise when they aren't expecting it, then there are the ones who can watch someone light a firecracker and still jump when it goes off. There are some theories like these: https://healthcare.utah.edu/the-scope/shows.php?shows=0_na1an0h6 Now the fun part. These are some mild ones.