First is legalization, if the certain person knows that bitcoin is not legal on his country then that person probably stop getting involved in bitcoin, second is the influence of media, because there are some medias that demote bitcoin or saying negative thoughts about bitcoin that can potentially scare people away from bitcoin. And i think the most common factor is the lack of knowledge, if he fully understand how bitcoin system works then he should know the potential of it, but if a certain person is lacking of that knowledge then he will be scared to put his money on