If we take people into account, there are a variety of reactions … There can be a case of no reaction to an action. There can be a delayed reaction. There also can be an over or an under reaction.. However, in all this list I seem to have assumed what a reaction is, based on which I have assumed the rest as hyper, hyo, under and above. Is there then a standard book of reactions to every situation? To me, a reaction unlike an action is very private to a person… They can decide how to react to a situation.