People tend to be afraid of what they don't know or understand. They are afraid to take on or learn something new when they should open their minds and give something new a try. What doesn't kill ya makes ya stronger.
I think that people in general are just afraid to stray away from what they already knowing. When we are accustomed to doing things a certain way, then we will allow no other way. Once we break down that wall and become more open-minded about the possibility of something being positive, we learn to explore new ideas and can quite possibly become fond of them.
I would like to say I concur with what has been said so far, rather insightful. I still would like to go a bit further by saying I believe too many people are just simply lazy. Often they take the word of someone they trust rather than making an effort to find out things for themselves, for example "you don't want to hang around with that person, they are a loser." How many times have we seen negative behavior from someone and once cornered we asked them why they behave that way-"that's just how I was raised."
People don't have to have these misconceptions about one another but too many of us find it easier to stick with these misconceptions than to make an effort to find out the truth for themselves.