There are people who encounter various events in their lives that will trigger them if they are going into a fight or flight mode. There are moments when the situations that people encounter are already considered to be too much that they develop a phobia towards that item or situation. It seems that most phobias may develop during early childhood.
Take note that there are also some people who develop their phobias later on in life. This is because of the possibility of going through a stressful situation, an experience or an event that has changed the way that a person thinks. Developing a phobia is not likely to occur beyond 30 years of age.