Also, there are different types of shrooms, saw at least 7 types last in Amsterdam, potency varied significantly. Also, how empty your stomach is makes world of difference. Also, method of consumption - dried vs fresh, raw/cooked, or like me mixing it with raw lemon juice (makes trip shorter but way more intense - 3g trips were full beyond reality with good setting).

Plus individual variation in digestion/enzymes/receptors/god knows what else is most probably also important.