Black and White In a Gray World

In debates I've had with some of my friends I have often been accused of wanting black and white answers. My friends assert that things are a lot grayer in the real world. It is true that we live in a complicated world and that there are hardly ever cut and dry answers that fit every situation. But my friends have missed what I was actually asking them. I was not and am not asking for a black and white answer that fits every situation. What I am asking for is why they believe the way they do and can they support it with scripture.
As Christians the Bible is supposed to be one of our moral plumb lines. (The Holy Spirit and fellow believers being some others). So when we, as Christians, go against something that seems fairly black and white in scripture I have to ask why. I am not doing this just to debate some issue (though I do love a good debate), but to get us to really think about why we believe something.
I had a friend in college whose grandmother was convinced "cleanliness is next to godliness" was in the Bible. I think a lot of Christians have similar misconceptions about what God's word says. It bugs me when someone claims the Bible says something that it doesn't (often the same people who send those urban legend emails -- grrr.) If you believe in Christ then your beliefs and actions should match up with his and his match up with the scripture.
I am not saying that there is no room for a different understanding of how scripture should be interpreted or seen. Most Christians would agree that polygamy and slavery are wrong, but these are both treated as acceptable in the Bible, clearly God has opened our eyes to better understand the scripture in these areas. But seeing scripture in a new light is different than ignoring it all together.