Their background, the atmosphere they have been brought up, their level of education, their social culture etc could have difference of thinking among individuals....
The main difference of thinking occurred by the life style that the individual have it.An individual how live life has more impact on his way of thinking about the matters.
I agree with chinmoy, everthing helps in building someonce charater. example is myself. by seeing me people think am a village girl and i didnt studied much as i wont look like modern. But when they speak to me and know about my qualification, my working status, my way of speaking and my skills and talent. they will be surprised and even they feel a good impression on me and even like to be my friend.
Education, family background, exposure to many experiences, regional characteristics and religious beliefs whether a believer or an atheist shapes up the way an individual thinks!