So then we got the Ten specific behaviors.  And that should've been enough, but we kept messing that up, too.  What exactly qualifies as coveting?  Is there a grey area around the "false" part of "false witness?"  And that led to the huge mess that makes up the rest of the first five books of the Bible.  And really, the whole mess that makes up the rest of the OT.  Our need for definition is what really called for Jesus to illustrate it.  And when we asked him what was important, he basically brought it all back 'round to "stick with me." 
I'm reminded of this all the time when students say they should get away with certain things because they aren't specifically forbidden in the published rules.  Don't they know what they're asking for when they say they want to live that way?  It saddens me that they don't get it.  And then I look at the way we, the supposed grown-ups, try to get around the letter of the law when we know darn well what the spirit of the law is, and it saddens me again that maybe none of us gets it. 
Thanks for the thoughtful post.  It's given me a lot to think about today.