John Howard Griffin did indeed experience the hardships of being black in Black Like Me. For one, he experienced how difficult it was to find what most of us take for granted: a bathroom. He also learned about peer pressure. Even though he was not required by law to give up a bus seat at the time the story takes place, he does start to give up his seat to a white woman as a common courtesy. When he does this, he meets with disapproval from his black "peers".
He also came to realize how improper treatment can lead to what society deems improper behavior. Black Like Me is a true story and Griffin was not recognizable as white during his "experiment"- so at times, it was impossible for him to experience anything except that of what a black person would experience at the time.