I think it happens because people don't know how to handle events outside their normal day-to-day activities. An example that many people can relate to is if someone dies, as a person reacts with different emotions, being that nobody has taught them what to think when this happens to someone close to them. If people encounter something very odd, they will do first anything they have been taught to do in such a situation. If not, they will do what they think their mother or father would have done, especially if they knew of their parents to have a strong attitude towards such a situation. Sans that, they will just do nothing or panic, depending on whether the situations affects them directly or not. This is from my own observation by the way.