I'm sure that I won't be right in all that I say, so I challenge others to write better. Although I think that most stories have minimal impact in shaping our lives, I do feel that certain types of stories can have major impact in influencing some attitudes, even though attitude is difficult to change when it is anchored emotionally. For example, when a thief has stolen something valuable from you, breeching your security and destroying your illusion of safety, your attitude becomes emotionally rooted. It becomes difficult to think of a thief in kindly terms. Emotion is a primary component in attitude, and it is very difficult to change an attitude once it has been shaped by emotion.
Attitude is also very difficult to change through education alone.
Knowledge is not very influential in changing strongly ingrained habits and beliefs, especially not if emotionally anchored. But certain types of stories are able to touch people both emotionally and intellectually, and empower attitude change in those who are receptive. For example, in Japan, those who are born with disabilities used to be viewed as a shame to their families. That kind of cultural image doesn't just evaporate - it takes a long time to change those attitudes. Hirotada Ototake was born with no limbs.