As defined by dictionary.com:
prej·u·dice: an unfavorable opinion or feeling formed beforehand or without knowledge, thought, or reason.
This is my definition of choice because it basically points out that if you say/do something with prejudice... you aren't using your brain.
Through social media I was exposed to 2 instances of it in the last 24 hours.
One was a comment about "white boys" and one was a comment about religion.
You know all the usual arguments against prejudice, you now know that it's defined in one way as not using your brain.
Let me throw this at you... I think most of the time it's just blatant lazy-ass stuff. It's not taking the time and effort to address individuals as people instead of just a member of a group.
I know very few (if any) people who think all "Religion is Evil" but it was the quote used, it's just lazy. Take the 3 seconds to type the word "some" and now you have "some Religion is evil" and it becomes a true, non-prejudice statement that can lead to good learning and quality discussion. Leave "some" out and you just attacked the beliefs, rituals, morals and Faith of over half the population. 99.9% of which you have never met to make a knowledgeable decision as to their character or intentions. May seem like semantics to you... but leaving out "some" puts about 4 billion people in a defensive posture and ruins a chance for good conversation from the get-go.
I don't know any Black people that think ALL 'White Boys have it easy' but that was the quote used. Same deal... No doubt as a whole "White Boys" in general have had it easier in the history of this world. But in 2012 to use it as an all encompassing phrase is no less prejudicial than if I started a statement with "You know ALL Black People...." ... Some "White boys" have it just as hard as anybody else in this world.
Really it's just laziness on our parts to not take the time to deal with people as individuals, it's the same reason our efforts to help those in need are flailing... you just can't find that super-convenient, all encompassing method to deal with large groups of people. We were meant to deal with individuals, get to know people and be their friends/help them individually.