before i learned psychology. i often laughing why people do this and that, why people could become that extreme when faced something, why people could be so much different with me when they did the exact same thing. now i know that one stimuli, one accident, one problem could extremely change a person cognitive scheme. now i know that the changing scheme which given many reinforcement could make the changing behavior. now i know that the new scheme is not an easy little thing, that person.. must be experienced times that they need to act so. this science teach me to respect, to appreciate and understand more about the most special creature named human.