Voice of truth

I find it very interesting how we tend to sift through suff we hear and belive to find what we want to hear or what feels okay or good.
I think this goes hand in hand, when we can be so consumed by what we think is right or true, and yet be blinded and miss what really was true and right.
We live in a world that says that we shoud follow what we think is right, but really how can we justify anything if everyone did what they thought was right, when it could be totally wrong?
I mean how far, and how sucessful is anyone who goes by their own truth?
It could include anything such as that they see stealing as okay, and a true thing to do, and yet is it right, or even close to the actual truth?
Can anyne of us actually say what is "true" unless we have taken it from God's word?