Talked

4:8 And Cain talked with Abel his brother: and it came to pass, when they were in the field, that Cain rose up against Abel his brother, and slew him.

Basic storytelling seems to be breaking down here.  What did they talk about?  Did Abel say something incredibly obnoxious (that is, God-like)?  I thought you were supposed to talk to people to work out your issues, not as a prelude to violence.  Does this have anything to do with the desire bit from the last verse?

So, God incited the first murder.  First, by demanding offerings for no reason.  Second, for insulting some of the offerings for no reason, while praising others.  Third, by mocking the one whose offering had been rejected; and by blaming him.  This seems all crafty and subtil and evil of God.  Also, sort of pointless.